Histopathology of drug rash with eosinophilia and systemic symptoms syndrome: a morphological and phenotypical study

Histopathologic Features in Vancomycin-Associated Drug-Induced Hypersensitivity Syndrome

BACKGROUND

Drug-induced hypersensitivity syndrome (DiHS), or drug reaction with eosinophilia and systemic symptoms (DRESS), is a delayed and severe immune response to certain medications. We investigated vancomycin-induced DiHS/DRESS, notable for frequent and severe organ involvement, to describe its specific histopathology and the correlations between histopathologic and clinical findings.

METHODS

A retrospective review was conducted to identify patients between 2006 and 2022 who received vancomycin, had archived skin biopsy specimens, and were scored as having probable or definite DiHS/DRESS. Clinical features were retrospectively collected, and biopsy specimens were reviewed by a board-certified dermatopathologist. A subset of histopathologic and clinical features was analyzed for statistical correlation.

RESULTS

Twenty-three patients met the inclusion criteria. Most biopsy specimens (87%) showed an eczematous reaction pattern; 17 (74%) showed a secondary reaction pattern. Spongiosis (87%) and neutrophilic infiltration (91%) were common epidermal characteristics. The dermal inflammatory infiltrate was frequently superficial (87%) and consistently included plasma cells (96%). Eosinophils were present in the dermis in 70% of cases. Parakeratosis negatively correlated with liver involvement and positively correlated with desquamative rash. Epidermal lymphocytes were negatively correlated with the RegiSCAR score.

CONCLUSIONS

Vancomycin-associated DiHS/DRESS histopathology was characterized by a frequent eczematous reaction pattern, multiple coexisting reaction patterns, and epidermal neutrophilic infiltration.

Diagnosing and Managing Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS) Amidst Remaining Uncertainty

Drug reaction with eosinophilia and systemic symptoms (DRESS), a severe cutaneous adverse reaction, represents a diagnostic and therapeutic challenge due to its varied, evolving clinical presentation, complex pathophysiology, and potential for severe systemic involvement. This article explores DRESS syndrome through 3 illustrative cases from diverse populations and with different background comorbidities. Cases highlight different challenges in DRESS care, including (1) the need for early diagnosis and severity scoring, (2) identification of offending drugs and risk stratification to consider a possible drug challenge, and (3) best practice management including long-term monitoring for emergent autoimmunity. Recent developments in our understanding of clinical spectrum of disease, genomic and nongenomic biomarkers, severity groupings, and pharmacological and longer-term management strategies are described. Critical gaps remain in several of these domains, particularly in vulnerable groups such as the immune-compromised. In the absence of robust evidence, we aim in this article to assist attending clinicians with current expert opinion in DRESS management. Finally, we highlight areas for further research needed to improve the clinical care and outcomes of DRESS.

Retinal Vasculopathy and Choroiditis after Pegcetacoplan Injection: Clinicopathologic Support for a Drug Hypersensitivity Reaction

PURPOSE

To report the detailed histopathology of 2 enucleated eyes from 2 patients who developed severe visual loss associated with retinal hemorrhages, vessel sheathing, and vascular nonperfusion after administration of an initial dose of intravitreal pegcetacoplan, and propose, with supportive histopathology, the pathogenesis of the clinical syndrome previously termed hemorrhagic occlusive retinal vasculitis.

DESIGN

Case series.

SUBJECTS

Two enucleated eyes from 2 patients treated with intravitreal pegcetacoplan.

METHODS

Retrospective, multicenter, consecutive clinical-pathologic analysis.

MAIN OUTCOME MEASURES

Histopathologic review and immunophenotypic characterization.

RESULTS

Both patients presented with inflammation and significant vision loss 9 days after the initial injection of pegcetacoplan with no subsequent improvement and underwent enucleation for pain control. Histologic examination of the enucleated eyes (patient 1 at 4 months postinjection and patient 2 at 40 days) revealed extensive vascular thrombosis, retinal hemorrhages and necrosis, and a dense inflammatory infiltrate in the uvea and, variably, the optic nerve, episclera, and muscle tendons composed of predominantly of T cells, macrophages, and eosinophils. Notably, the inflammatory infiltrate was absent from the retina. In addition, 1 eye demonstrated multiple foci of glomerular-like vascular proliferations in the uveal tract and thrombosis with focal recanalization of vessels in the optic nerve.

CONCLUSIONS

Drug-induced, immune-mediated, retinal vasculopathy and choroiditis (DIRVAC) is a rare complication after pegcetacoplan injection. Although some limitations arise in interpretation of histopathologic findings because of compensatory changes in the eyes over time (before enucleation), the authors propose that the combined clinical, histopathologic, and immunohistochemical findings suggest a mixed-type, delayed hypersensitivity reaction as the mechanism of initial injury.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Guidelines for the management of drug-induced hypersensitivity syndrome 2023

Drug-induced hypersensitivity syndrome (DIHS) is one of the severe drug eruptions accompanied by fever and multiple organ dysfunction, and it is induced by a relatively limited range of drugs, including anticonvulsants. A distinctive feature of this condition is its association with the reactivation of herpes viruses, particularly human herpesvirus 6. The pathogenesis involves two key factors: drug allergy and herpesvirus reactivation. DIHS is often challenging to diagnose in its early stages, and its clinical course varies widely, ranging from relatively mild to life-threatening cases. Additionally, unexpected complications, such as autoimmune diseases, may occur during the convalescent phase. As a result, diagnosing, treating, and predicting the prognosis of DIHS remain complex issues. In response to these challenges, the Ministry of Health, Labour and Welfare Study Group on Severe Erythema Multiforme has taken the lead in developing new guidelines for the management of DIHS. These guidelines aim to support clinical practice by providing up-to-date, evidence-based information on the diagnosis, treatment, and prognosis of DIHS.

Fatal outcome related to drug reaction with eosinophilia and systemic symptoms: a disproportionality analysis of FAERS database and a systematic review of cases

Background

Drug rash with eosinophilia and systemic symptoms (DRESS) is a life-threatening severe cutaneous adverse reaction.

Objective

This study aims to study fatal DRESS cases using FAERS database and systematic review.

Methods

Data of the FDA Adverse Event Reporting System (FAERS) database were extracted and manipulated. Articles from Pubmed, Embase and CINAHL databases were screened.

Results

0.13% of the adverse events submitted to FAERS was identified as DRESS and the percentage of fatal cases was up to 6.62%. The top five drugs calculated to induce DRESS with the highest number of reported cases were allopurinol, lamotrigine, vancomycin, amoxicillin and carbamazepine. The top five drugs statistically related to fatal outcome with the highest number of reported cases were allopurinol, vancomycin, trimethoprim, sulfamethoxazole and lamotrigine. Skin manifestations remained the main reason for admission and the average time from dose to rash onset was 27.19 days. The most commonly cited culprit medication type were antibiotics (50.00%), anti-gout agents (15.38%) and anti-epileptic drug (11.54%).

Conclusions

We discussed fatal cases of DRESS through FAERS system and case reports, hoping to raise awareness when using relevant drugs.

Vesiculopustular drug reaction with eosinophilia and systemic symptoms induced by levetiracetam

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe cutaneous adverse reaction characterised by fever, lymphadenopathy, morbilliform rash, haematologic abnormalities, and multiorgan involvement. Herein, we describe a 32-year-old female presenting with a 9-day history of facial oedema, cervical and inguinal lymphadenopathy, and a pruritic rash comprised of vesicles and pustules on her face, trunk, and extremities. Her only medications were valproate, which she had been taking for several years, and levetiracetam, which was initiated 41 days prior to rash onset. On the 16th day of her rash, she was diagnosed with DRESS induced by levetiracetam (Registry of Severe Cutaneous Adverse Reactions: 5). At this point, her absolute eosinophil count was 0.9 × 109 cells/L and aspartate and alanine transaminase levels were 357 and 339 U/L, respectively. Pustules with a morbilliform rash may occur in up to 30% of DRESS cases. In rarer instances, as in our patient, DRESS can present with isolated pustules and vesicles. Similarly, although rare, DRESS can be induced by levetiracetam.

Drug Allergy Mimics

When approaching a case of apparent drug allergy, the consulting clinician should consider a broad differential diagnosis. This article presents a series of cases that could be commonly referred to an allergist for assessment as "drug allergy," however, a real diagnosis exists that mandates a different diagnostic and treatment strategy, including a case of inducible laryngeal obstruction, multiple drug intolerance syndrome, viral rash, seizure due to metastatic malignancy, and hemophagocytic lymphohistiocytosis initially diagnosed as drug reaction and eosinophilia with systemic symptoms. The initial misdiagnoses of these patients delayed or interfered with their medical care, emphasizing the importance of accurate diagnoses for the benefit of our patients.

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms. Part II diagnosis and management

Drug-induced hypersensitivity syndrome, also known as drug reaction with eosinophilia and systemic symptoms, is a severe cutaneous adverse reaction characterized by an exanthem, fever, and hematologic and visceral organ involvement. The differential diagnosis includes other cutaneous adverse reactions, infections, inflammatory and autoimmune diseases, and neoplastic disorders. Three sets of diagnostic criteria have been proposed; however, consensus is lacking. The cornerstone of management is immediate discontinuation of the suspected drug culprit. Systemic corticosteroids remain first-line therapy, but the literature on steroid-sparing agents is expanding. Longitudinal evaluation for sequelae is recommended. Adjunctive tests for risk stratification and drug culprit identification remain under investigation. Part II of this continuing medical education activity begins by exploring the differential diagnosis and diagnosis of drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms and concludes with an evidence-based overview of evaluation and treatment.

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms. Part I. Epidemiology, pathogenesis, clinicopathological features, and prognosis

Drug-induced hypersensitivity syndrome (DiHS), also known as drug reaction with eosinophilia and systemic symptoms (DRESS), is a severe cutaneous adverse reaction (SCAR) characterized by an exanthem, fever, and hematologic and visceral organ involvement. Anticonvulsants, antibiotics, and allopurinol are the most common triggers. The pathogenesis involves a complex interplay between drugs, viruses, and the immune system primarily mediated by T-cells. DiHS/DRESS typically presents with a morbilliform eruption 2-6 weeks after drug exposure, and is associated with significant morbidity, mortality, and risk of relapse. Long-term sequelae primarily relate to organ dysfunction and autoimmune diseases. Part I of this continuing medical education activity on DiHS/DRESS provides an update on epidemiology, novel insights into pathogenesis, and a description of clinicopathological features and prognosis.

Cutaneous adverse drug reactions

Cutaneous adverse drug reactions (ADRs) represent a heterogeneous field including various clinical patterns without specific features suggesting drug causality. Maculopapular exanthema and urticaria are the most common types of cutaneous ADR. Serious cutaneous ADRs, which may cause permanent sequelae or have fatal outcome, may represent 2% of all cutaneous ADR and must be quickly identified to guide their management. These serious reactions include bullous manifestations (epidermal necrolysis i.e. Stevens-Johnson syndrome and toxic epidermal necrolysis), drug reaction with eosinophilia and systemic symptoms (DRESS) and acute generalized exanthematous pustulosis (AGEP). Some risk factors for developing cutaneous ADRs have been identified, including immunosuppression, autoimmunity or genetic variants. All drugs can cause cutaneous ADRs, the most commonly implicated being antibiotics (especially aminopenicillins and sulfonamides), anticonvulsants, allopurinol, antineoplastic drugs, non-steroidal anti-inflammatory drugs and iodinated contrast media. Pathophysiology is related to immediate or delayed "idiosyncratic" immunologic mechanisms, i.e., usually not related to dose, and pharmacologic/toxic mechanisms, commonly dose-dependent and/or time-dependent. If an immuno-allergic mechanism is suspected, allergological explorations (including epicutaneous patch testing and/or intradermal test) are often possible to clarify drug causality, however these have a variable sensitivity according to the drug and to the ADR type. No in vivo or in vitro test can consistently confirm the drug causality. To determine the origin of a rash, a logical approach based on clinical characteristics, chronologic factors and elimination of differential diagnosis (especially infectious etiologies) is required, completed with a literature search. Reporting to pharmacovigilance system is therefore essential both to analyze drug causality at individual level, and to contribute to knowledge of the drug at population level, especially for serious cutaneous ADRs or in cases involving newly marketed drugs.

Assessing delayed penicillin hypersensitivity using the PENFAST+ score

Introduction

Approximately 10% of individuals report a suspected allergy to penicillin, but according to allergy work-ups, only 10%-15% of them are truly allergic. A clinical decision score, the PEN-FAST, was developed and validated to identify adults with low-risk penicillin allergy.

Objectives

The objective of this study was to improve the performance of the PEN-FAST score, particularly for those with delayed hypersensitivity (HS), by improving the negative predictive value.

Methods

STEP 1: Retrospective evaluation of the PEN-FAST score in patients with proven immediate and delayed penicillin allergy. STEP 2: Identification of additional criteria among Step 1 patients misclassified by PEN-FAST score. Development of the PEN-FAST+ score using multivariable logistic regression in a prospective cohort of patients with a suspicion of HS to penicillin. STEP 3: Comparison of diagnostic performances of PEN-FAST and PEN-FAST+ scores.

Results

The PEN-FAST score showed limitations in predicting the relapse of immediate skin HS or delayed maculopapular exanthema, with 28.6% and 38.4% of patients misclassified, respectively. We identified two potential additional criteria: skin rash lasting more than 7 days and immediate reaction occurring in less than 1 h (generalized or localized on palmoplantar area or scalp itching/heat feeling). A total of 32/252 (12.7%) patients were confirmed to be allergic to penicillin. With PEN-FAST, 37% of patients (n = 10) with delayed allergic penicillin HS were misclassified. With PEN-FAST+, 3 patients with delayed HS confirmed by a ST (11.1%) were misclassified. The AUC was significantly higher for PEN-FAST+ than PEN-FAST (85% vs. 72%, p = 0.03).

Unraveling the complexities of drug reaction with eosinophilia and systemic symptoms (DRESS): Insights into clinical, laboratory, and histopathologic features of a case series from an Italian tertiary center

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe and potentially life-threatening drug hypersensitivity reaction. The diagnosis and management of DRESS are complicated due to its heterogeneous clinical and pathologic presentations, delayed onset of signs and symptoms, and unpredictable outcome. This retrospective study aimed to analyze cases of DRESS from a single Italian referring tertiary hospital center (Grande Ospedale Metropolitano Niguarda, Milan, Italy) with a focus on clinical features, causative drugs, histopathologic findings, and treatment. We have included 18 of 32 patients with a probable or definite diagnosis of DRESS. The study observed a slight predominance of women, with antimicrobials and allopurinol identified as the main causative drugs. Clinical manifestations varied, with a monomorphic maculopapular eruption being the most common, whereas facial edema and mucosal involvement were less frequently observed. Multiple organs were commonly affected, with liver and kidney involvement being prominent. Cardiac involvement was associated with the severity of eosinophilia. Laboratory evaluations showed elevated eosinophil levels and increased eosinophil cationic protein levels, supporting the role of eosinophils in DRESS pathogenesis. Histopathologic analysis revealed various patterns often coexisting in the same biopsy in 83% of cases, with interface dermatitis being the most frequent, followed by the perivascular pattern and the spongiotic/eczematous pattern. We observed eosinophils in the biopsy samples in about 50% of patients, and the relationship between peripheral eosinophilia and eosinophils in skin biopsies was not significant. In addition to the RegiSCAR score, age may play a role in predicting disease severity, as older patients with lower scores had poorer outcomes. The prognosis of DRESS depended on early identification, discontinuation of the causative agent, and appropriate therapy. Systemic corticosteroids were the primary treatment option.

Expanding the Histologic Spectrum of Sudden Conjunctivitis, Lymphopenia, and Rash Combined With Hemodynamic Changes

ABSTRACT

Sudden conjunctivitis, lymphopenia, and rash combined with hemodynamic changes (SCoRCH) is a recently described hypersensitivity reaction to trimethoprim-sulfamethoxazole. To date, only 1 case of histologic findings in SCoRCH has been reported, revealing a superficial perivascular dermatitis. In this article, we present a 53-year-old woman with a four-day history of a widespread, confluent, erythematous, and dusky rash after exposure to trimethoprim-sulfamethoxazole. Histologic examination revealed a vacuolar interface dermatitis with several apoptotic keratinocytes at multiple levels of the epidermis, similar to an erythema multiforme-like presentation. As described in SCoRCH, our patient's clinical findings rapidly improved within 48 hours of presentation without treatment. This case adds to the current literature by identifying a newly described histopathological presentation of SCoRCH.

DRESS syndrome: A literature review and treatment algorithm

Drug reaction with eosinophilia and systemic symptoms, known by its acronym in English as DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms), clinically manifests with fever, facial edema, lymphadenopathy, a morbilliform rash, and organ involvement. Laboratory results reveal leukocytosis, atypical lymphocytes, eosinophilia, and alterations of liver and kidney function tests. The actual incidence of DRESS is unknown, because it may vary depending on the type of medication and the immune status of each patient; also, because many cases remain undiagnosed or untreated. The drugs most associated with DRESS include antiepileptics, antibiotics, antituberculosis, and non-steroidal anti-inflammatory agents (NSAIDs). Its diagnosis is sometimes made late and can become a challenge. The diagnostic criteria proposed by the international Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) help to establish the diagnosis through a score system based on clinical and laboratory findings. The first step to identify the culprit is a thorough clinical history that includes all suspects, emphasizing those most known to cause DRESS syndrome according to the context and the literature. A skin biopsy may also be helpful in the diagnostic process. Patch testing is the test of choice to search for the culprit in cases of DRESS. Regarding prognosis, the estimated mortality due to DRESS is 3.8%. The main causes of mortality include fulminant hepatitis and liver necrosis. Several indicators of poor prognosis have been identified and these include an eosinophil count above 6000 × 103/μL, thrombocytopenia, pancytopenia, leukocytosis and coagulopathy. This article aims to review the evidence available regarding the epidemiology, pathophysiology, clinical and laboratory findings, diagnosis, and treatment of DRESS.

A Case of Primary Epstein-Barr Virus Infection Masquerading As Drug Reaction With Eosinophilia and Systemic Symptoms

In this case report, we discuss the diagnostic dilemma presented by a patient admitted for elevated liver enzymes and rash, who had a history of recent amoxicillin use. This presentation initially appeared to fit the criteria for Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome. However, histologic evaluation determined the rash was consistent with Miliaria rubra rather than the lymphocytic infiltrate of DRESS. This necessitated broad diagnostic testing to determine the underlying etiology of the patient's syndrome. Serology subsequently demonstrated primary Epstein-Barr Virus (EBV) infection, which explained her acute liver injury. Her eosinophilia was potentially related to an allergic reaction to surgical tape but was never definitely diagnosed. This case demonstrates the importance of maintaining a wide differential even when clinical diagnostic criteria are apparently met.

Drug rash with eosinophilia and systemic symptoms syndrome masquerading as a lymphoproliferative disorder in a young adult on immunosuppressive therapy for rheumatoid arthritis: a case report

Background

This case reveals a novel presentation of drug rash with eosinophilia and systemic symptoms syndrome that mimics a lymphoproliferative disorder. The heterogeneous clinical presentation of drug rash with eosinophilia and systemic symptoms syndrome gives rise to a broad differential diagnosis that includes a multitude of infectious, inflammatory, and autoimmune conditions. This patient was diagnosed with drug rash with eosinophilia and systemic symptoms syndrome 4 weeks after starting sulfasalazine and 5 weeks after starting hydroxychloroquine for rheumatoid arthritis. Both of these medications have been shown to cause drug rash with eosinophilia and systemic symptoms syndrome, albeit more rarely in the context of hydroxychloroquine. This patient’s history, physical examination, and workup illuminate a case of drug rash with eosinophilia and systemic symptoms syndrome that masquerades as a lymphoproliferative disorder despite its adherence to the RegiSCAR criteria.

Case presentation

A 22-year-old African-American female with an atopic history and rheumatoid arthritis presented for evaluation of a rash, unremitting fevers, and syncope. She was found to have drug rash with eosinophilia and systemic symptoms syndrome. A syncope workup was unremarkable. Computed tomography of the chest/abdomen/pelvis confirmed extensive lymphadenopathy and revealed a small right pleural effusion (Fig. 5). These imaging findings accompanied by fevers and a rash in the setting of eosinophilia, leukocytosis, and transaminitis led to the clinical suspicion for drug rash with eosinophilia and systemic symptoms syndrome. Steroids were subsequently initiated. Broad-spectrum antibiotic therapy was implemented to cover for possible skin/soft tissue infection due to initial paradoxical worsening after discontinuation of the culprit drugs. Lymph node biopsy ruled out a lymphoproliferative disorder and instead demonstrated necrotizing lymphadenitis. An extensive infectious and autoimmune workup was noncontributory. Clinical improvement was visualized, antibiotics were discontinued, and she was discharged on a steroid taper.

Conclusion

This case reflects how drug rash with eosinophilia and systemic symptoms syndrome can masquerade as a lymphoproliferative disorder. Additionally, it highlights the extent to which rapid identification and treatment optimized the patient’s outcome. It calls into question how immunogenetics may factor into a patient’s susceptibility to acquire drug rash with eosinophilia and systemic symptoms syndrome. This case is unique because of the early onset of visceral organ involvement, the type of internal organ involvement, the hematopoietic features, and the lymphadenopathy associated with a disease-modifying antirheumatic drug.

How to Recognize and Manage Challenging DRESS Cases: Two Case Reports and A Review of the Literature

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is an uncommon systemic adverse drug reaction. Furthermore, it is a unique syndrome encompassing various manifestations of fever, facial edema, eosinophilia, atypical lymphocytosis, and organ dysfunction. Since there are no large prospective studies concerning DRESS syndrome, current treatment modalities for DRESS have been mainly determined based on various case reports and expert opinions. Corticosteroids are the mainstay of therapy after the cessation of the culprit drug. Although most cases recover within a couple of months, some may persist and even progress despite 1 mg/kg/day of prednisolone or its equivalent. We herein present two cases of severe DRESS syndrome. Both cases presented with organ dysfunction and remained unresponsive to initial treatment with 1 mg/kg/day of intravenous methylprednisolone. Therefore, plasmapheresis or pulse steroid therapy (250 mg/day methylprednisolone for three days) was used. In the follow-up period, patients' clinical conditions improved dramatically without recurrence. We aimed to share our experience in recognizing and managing severe DRESS cases in this manuscript. Furthermore, we reviewed the literature in comparison with the present cases. In conclusion, plasmapheresis or pulse steroid therapy (250 mg/day of methylprednisolone for three days) can be used to treat difficult DRESS cases where organ failure is about to happen.

The Mixed Spongiotic and Interface Reaction Pattern: A Study of Clinical and Histopathologic Findings

BACKGROUND

Categorization of biopsy specimens into inflammatory reaction patterns is central to dermatopathologic assessment. Mixed inflammatory patterns are poorly characterized and may represent clinicopathologic challenges. The purpose of this study was to identify clinical and histopathologic findings associated with the mixed spongiotic-interface dermatitis (SID) histopathologic pattern.

METHODS

Fifty-one institutional biopsy specimens of SID were identified over a 2-year period by retrospective natural language search. Histopathologic and clinical features were identified.

RESULTS

The most common histopathologic features associated with SID were mild spongiosis (51%), focal vacuolar interface change (72%), lymphocytic exocytosis (92%), and superficial-dermal lymphocytic infiltrate (94%) with variable eosinophils (61%). Clinically, 80% of subjects presented with a symmetric morbilliform eruption. Polypharmacy (94%), immunosuppression (47%), and history of malignancy (47%) were common. The most common diagnoses were drug reaction (37%), possible drug reaction (12%), and viral exanthem (12%). Drug reaction with eosinophilia and systemic symptoms represented 25% of all confirmed cutaneous adverse drug reactions (CADR). Average time from drug initiation to symptom initiation was 20 days (SD: 22.3, range: 0-90); median disease duration was 25.5 days. Spongiotic vesicles and Langerhans cells were less common in patients with a strong clinicopathologic diagnosis of drug reaction compared to non-drug eruptions (p = 0.04).

CONCLUSIONS

The mixed SID pattern is commonly encountered in CADR but may represent a more subacute course, implying consideration for inciting medication(s) started before the typical 7- to 14-day window.

Challenging Dermatologic Considerations Associated with Immune Checkpoint Inhibitors

Immune checkpoint inhibitors have emerged as a new paradigm in oncologic care for many malignancies. However, nonspecific immune activation has led to "collateral damage" in the form of immune-related adverse events, with skin being a commonly affected organ. Cutaneous immune-related adverse events include a wide spectrum of clinical presentations and challenging considerations, often necessitating dermatology referral to support diagnosis and management, particularly for atypical presentations or more severe, cutaneous immune-related adverse events that may require specialized dermatologic evaluations including biopsy and histopathology. Close collaborations between oncologists and dermatologists may optimize clinical decision making in the following challenging management settings: non-steroidal therapies for corticosteroid-refractory, cutaneous immune-related adverse events, immune checkpoint inhibitor rechallenge, balancing cutaneous immune-related adverse events and treatments, and immune checkpoint inhibitors in patients with pre-existing autoimmune disease, skin conditions, and organ transplants. These complex clinical decisions that often lack rigorous data should be made in close collaboration with dermatologists to minimize unnecessary morbidity and mortality. This article provides a review of approaches to challenging dermatologic considerations associated with immune checkpoint inhibitor therapies.

Drug-Induced vs. Viral Maculopapular Exanthem—Resolving the Dilemma

Maculopapular exanthem is a commonly encountered presentation in routine clinical practice, and differentiation between its two most common etiologies, i.e., viral- and drug-induced, often poses a diagnostic dilemma. Clinical, hematological and biochemical investigations are seldom reliable in distinguishing between a drug reaction and a viral exanthem. Certain key histopathological features such as the presence of a moderate degree of spongiosis, extensive basal cell damage with multiple necrotic keratinocytes and dermal infiltrate rich in eosinophils or lymphocytes and histiocytes may favor a drug exanthem, while distinctive epidermal cytopathic changes and lymphocytic vasculitis point towards a viral etiology. Similarly, notable immunohistochemical markers such as IL-5, eotaxin and FAS ligand may support a diagnosis of a drug-induced maculopapular eruption. Histopathological and immunohistochemical evaluations may help in distinguishing between the two etiologies when faced with a clinical overlap, especially in patients on multiple essential drugs when drug withdrawal and rechallenge is not feasible.

Drug Reaction with Eosinophilia and Systemic Symptoms (DReSS)/Drug-Induced Hypersensitivity Syndrome (DiHS)-Readdressing the DReSS

Drug reaction with eosinophilia and systemic symptoms (DReSS), also known as drug-induced hypersensitivity syndrome (DiHS), is a severe, systemic, T cell mediated drug reaction with combinations of cutaneous, hematologic, and internal organ involvement. Pathogenesis of DReSS is multi-factorial, involving drug-exposure, genetic predisposition through specific human leukocyte antigen (HLA) alleles and metabolism defects, viral reactivation, and immune dysregulation. Clinical features of this condition are delayed, stepwise, and heterogenous, making this syndrome challenging to recognize and diagnose. Two sets of validated diagnostic criteria exist that can be employed to diagnose DReSS/DiHS. Methods to improve early recognition of DReSS and predict disease severity has been a recent area of research focus. In vitro and in vivo tests can be employed to confirm the diagnosis and help identify culprit drugs. The mainstay treatment of DReSS is prompt withdrawal of the culprit drug, supportive treatment, and immunosuppression depending on the severity of disease. We present a comprehensive review on the most recent research and literature on DReSS, with emphasis on pathogenesis, clinical features, diagnosis, confirmatory testing modalities, and treatment. Additionally, this summary aims to highlight the differing viewpoints on this severe disease and broaden our perspective on the condition known as DReSS.

Histopathologic Features of Maculopapular Drug Eruption

Background: Cutaneous adverse drug reaction (CADR) is common in both inpatient and outpatient clinical settings and has been associated with a large variety of medications. Drug reactions represent a significant burden to the healthcare system due to increased hospital stay durations and associated costs. Moreover, some of these reactions may be life-threatening. The most common clinical manifestation of a CADR is a maculopapular drug eruption (MDE). Due to its many clinical mimics and associations with a variety of histopathologic patterns, maculopapular drug eruption is difficult to definitively diagnose from both a clinical and histopathological perspective. Summary: We reviewed the clinical and histopathologic features of 327 cases of MDE from several studies in the literature and summarized characteristic histopathologic findings and their frequencies of occurrence. We found that the most common and suggestive histopathologic features of MDE were epidermal spongiosis, lymphocytic infiltrate, and occasional necrotic keratinocytes; interface change at the DEJ; superficial perivascular and interstitial lymphocytic infiltrate with or without eosinophils and neutrophils in the mid-to-deep dermis and mild papillary dermal edema; and dilation of superficial vessels. The presence of multiple histopathologic patterns within the same tissue specimen is also suggestive of MDE. This review and analysis suggest that a biopsy may improve the diagnostic accuracy by both establishing common and uncommon features associated with MDE and reviewing features that help to exclude other causes of maculopapular eruption. Key Message: Histopathologic criteria for the diagnosis of MDE, while not entirely specific, may aid in establishing a differential that includes a drug eruption. Thus, a biopsy can be a helpful diagnostic tool when MDE is suspected by demonstrating findings suggestive of MDE or by ruling out clinical mimics. However, biopsy results cannot be used in isolation as clinical-pathologic correlation is paramount in MDE.

Severe delayed hypersensitivity reactions to IL-1 and IL-6 inhibitors link to common HLA-DRB1*15 alleles

OBJECTIVES

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe, delayed hypersensitivity reaction (DHR). We observed DRESS to inhibitors of interleukin 1 (IL-1) or IL-6 in a small group of patients with Still's disease with atypical lung disease. We sought to characterise features of patients with Still's disease with DRESS compared with drug-tolerant Still's controls. We analysed human leucocyte antigen (HLA) alleles for association to inhibitor-related DHR, including in a small Kawasaki disease (KD) cohort.

METHODS

In a case/control study, we collected a multicentre series of patients with Still's disease with features of inhibitor-related DRESS (n=66) and drug-tolerant Still's controls (n=65). We retrospectively analysed clinical data from all Still's subjects and typed 94/131 for HLA. European Still's-DRESS cases were ancestry matched to International Childhood Arthritis Genetics Consortium paediatric Still's cases (n=550) and compared for HLA allele frequencies. HLA association also was analysed using Still's-DRESS cases (n=64) compared with drug-tolerant Still's controls (n=30). KD subjects (n=19) were similarly studied.

RESULTS

Still's-DRESS features included eosinophilia (89%), AST-ALT elevation (75%) and non-evanescent rash (95%; 88% involving face). Macrophage activation syndrome during treatment was frequent in Still's-DRESS (64%) versus drug-tolerant Still's (3%; p=1.2×10-14). We found striking enrichment for HLA-DRB1*15 haplotypes in Still's-DRESS cases versus INCHARGE Still's controls (p=7.5×10-13) and versus self-identified, ancestry-matched Still's controls (p=6.3×10-10). In the KD cohort, DRB1*15:01 was present only in those with suspected anakinra reactions.

CONCLUSIONS

DRESS-type reactions occur among patients treated with IL-1/IL-6 inhibitors and strongly associate with common HLA-DRB1*15 haplotypes. Consideration of preprescription HLA typing and vigilance for serious reactions to these drugs are warranted.

Drug Reaction with Eosinophilia and Systemic Symptoms and Agranulocytosis Presenting as Cervical Lymphadenopathy

Objective: Drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare cause of cervical lymphadenopathy. It is a potentially life-threatening hypersensitivity reaction, commonly characterized by fever, rash, hematological abnormalities, and multi-organ involvement. Its association with agranulocytosis is even rarer, with fewer than 10 cases describing the coexistence of DRESS with agranulocytosis reported in the English literature. Case Summary: An otherwise well 40-year-old female presented with a sore throat and cervical lymphadenopathy, with investigations revealing DRESS and agranulocytosis secondary to carbamazepine. Conclusion: DRESS and agranulocytosis are serious, potentially life-threatening adverse drug reactions which can initially present as cervical lymphadenopathy. As carbamazepine is considered first-line therapy for certain chronic neuropathic conditions such as trigeminal neuralgia, clinicians should be aware of the varying clinical presentations of both conditions.

Histopathological characterization of drug rash with eosinophilia and systemic symptoms (DRESS) and comparison with maculopapular drug rash (MPDR)

Introduction:

Drug rash with eosinophilia and systemic symptoms (DRESS) is a severe cutaneous adverse drug reaction (cADR) associated with significant systemic involvement and greater mortality. Variable patterns of inflammation are reported in the histopathology of DRESS. However, the role of histopathology in predicting systemic involvement and thus final outcome remains elusive. In the present study, we aim to review clinical and histopathological characteristics of patients with DRESS and compare their histopathology with that of maculopapular drug rash.

Materials and Methods:

A retrospective analysis of cases of cADRs diagnosed from July 2014 to July 2020 at a single tertiary care institute was performed. A RegiSCAR score of ≥4 was used to recruit patients as DRESS. Patients with a probable/definite diagnosis of cADR on the basis of Naranjo criteria and presenting with exanthem attaining a RegiSCAR score of ≤3 were categorized as MPDR. Correlation of histopathology characteristics with the investigative profile of patients with DRESS was done. MPDR and DRESS were also compared for histopathological characteristics using Chi-square test. Further histopathology of patients with drug rash (both DRESS and MPDR) having systemic involvement was compared with those without systemic involvement to identify specific predictors.

Results:

Eighteen patients of DRESS and 20 of MPDR fulfilled the inclusion criteria. Most common drugs implicated were anticonvulsants (27.8%). Characteristic findings seen on histopathology in patients with DRESS were epidermal spongiosis (94.5%), epidermal dyskeratosis (33.3%), lymphocytic exocytosis (88.9%), interface vacuolization (77.8%), papillary dermal edema (100%). and perivascular lymphocytic infiltrate (100%). Findings in favor of DRESS compared to MPDR were lymphocytic exocytosis (P < 0.001), interface vacuolization (P = 0.002), severe spongiosis (P = 0.046), severe papillary dermal edema (P = 0.018), and higher density of dermal infiltrate (P = 0.005). Lymphocyte exocytosis and distribution and density of dermal inflammatory infiltrate correlated significantly with deranged kidney function.

Conclusion:

Histopathology revealing prominent basal vacuolization, spongiosis, and dense dermal infiltrate suggests DRESS. Lymphocyte exocytosis and distribution and density of dermal inflammatory infiltrate predict renal involvement.

Nivolumab-associated DRESS in a genetic susceptible individual

The use of immune checkpoint inhibitors (ICIs) is rising exponentially in numerous cancers, but immune-related adverse events can occur. We report a rare case of high-grade drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome developed stepwise in a patient with gastric cancer after nivolumab treatment. Subclinical myocarditis was sensitively detected by cardiovascular magnetic resonance 3 weeks after initiating nivolumab. Eruption, eosinophilia, and interstitial pneumonitis occurred 1 week later. Corticosteroids were started and his condition improved. Four months later, when he was still on steroids tapering off, acute kidney injury and sequential herpes zoster virus activation developed. Severe acute tubulointerstitial nephritis (ATN) with an intense infiltration of lymphocytes was observed on renal biopsy. In blood, a substantial shift to Th2 response, an increase of Th17 cells, and strikingly enriched granzyme B+ and perforin+ CD8+ T cells were detected at ATN onset. Serum interleukin (IL)-5, IL-17, interferon gamma, and IL-6 levels were consistently elevated. Further molecular profiling identified a DRESS risk allele human leukocyte antigen (HLA)-A*31:01 in this patient. His ATN responded favorably to a high dose of corticosteroids. In parallel, complete antitumor response was observed during the clinical course of DRESS. This is the first ever case report of nivolumab-associated DRESS syndrome with exploration of the mechanisms from the histopathological, cellular and molecular aspects. Nivolumab-induced DRESS may result from type IV hypersensitivity-related 'off-target effect' and PD-1 block-mediated 'on-target effect'. HLA risk alleles may constitute the genetic susceptible basis. HLA typing assay has the potential to screen susceptible individuals to avoid ICI-induced DRESS.

Case Report: Alpelisib-Induced Drug Reaction With Eosinophilia and Systemic Symptoms: A Rare Manifestation of a Common Side Effect

Alpelisib is a PIK3a inhibitor approved for the treatment of metastatic ER+ breast cancer in combination with fulvestrant. Although rash is a common side effect of this medication, we present the first case of drug reaction with eosinophilia and systemic symptoms (DRESS) upon initial exposure to alpelisib. Here we describe the clinical-pathological findings and management of our patient with alpelisib-induced life-threatening DRESS syndrome. The goal of this case report is to highlight association of alpelisib with DRESS syndrome, in clinical practice, so that alpelisib can be immediately stopped and treatment for this serious condition promptly initiated.

Developing a standardized approach for assessing mast cells and eosinophils on tissue biopsies: A Work Group Report of the AAAAI Allergic Skin Diseases Committee

Mast cells and eosinophils are commonly found, expectedly or unexpectedly, in human tissue biopsies. Although the clinical significance of their presence, absence, quantity, and quality continues to be investigated in homeostasis and disease, there are currently gaps in knowledge related to what constitutes quantitatively relevant increases in mast cell and eosinophil number in tissue specimens for several clinical conditions. Diagnostically relevant thresholds of mast cell and eosinophil numbers have been proposed and generally accepted by the medical community for a few conditions, such as systemic mastocytosis and eosinophilic esophagitis. However, for other mast cell- and eosinophil-associated disorders, broad discrepancies remain regarding diagnostic thresholds and how samples are processed, routinely and/or specially stained, and interpreted and/or reported by pathologists. These discrepancies can obfuscate or delay a patient's correct diagnosis. Therefore, a work group was assembled to review the literature and develop a standardized consensus for assessing the presence of mast cells and eosinophils for a spectrum of clinical conditions, including systemic mastocytosis and cutaneous mastocytosis, mast cell activation syndrome, eosinophilic esophagitis, eosinophilic gastritis/enteritis, and hypereosinophilia/hypereosinophilic syndrome. The intent of this work group is to build a consensus among pathology, allergy, dermatology, hematology/oncology, and gastroenterology stakeholders for qualitatively and quantitatively assessing mast cells and eosinophils in skin, gastrointestinal, and bone marrow pathologic specimens for the benefit of clinical practice and patients.

Cutaneous adverse events caused by immune checkpoint inhibitors

IMPORTANCE

Immune checkpoint inhibitors (ICIs) have emerged as active therapies for a variety of cancers. Cutaneous toxicities are common immune-related adverse events and patients will often be referred to dermatologists for evaluation.

OBSERVATIONS

Cutaneous adverse events to ICIs can have a variety of clinical presentations. Among the more common are eczematous, morbilliform, and lichenoid dermatoses, as well as vitiligo and pruritus. Less common adverse events include psoriasiform dermatoses, bullous disorders, and severe cutaneous adverse reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms. Because of the immunologic mechanism of ICIs, there are also a variety of rheumatologic adverse reactions with cutaneous manifestations, such as scleroderma, dermatomyositis, cutaneous lupus erythematosus, and various vasculitides. These cutaneous reactions often respond to topical or systemic steroids, although specific toxicities may have alternative treatments available.

CONCLUSIONS AND RELEVANCE

As they become more widely prescribed, dermatologists will see an increasing number of patients with cutaneous adverse events caused by ICI therapies. Accurately diagnosing and treating these toxicities is paramount to achieving the most favorable outcomes for patients.

The Emerging Role of the Innate Immune Response in Idiosyncratic Drug Reactions

Idiosyncratic drug reactions (IDRs) range from relatively common, mild reactions to rarer, potentially life-threatening adverse effects that pose significant risks to both human health and successful drug discovery. Most frequently, IDRs target the liver, skin, and blood or bone marrow. Clinical data indicate that most IDRs are mediated by an adaptive immune response against drug-modified proteins, formed when chemically reactive species of a drug bind to self-proteins, making them appear foreign to the immune system. Although much emphasis has been placed on characterizing the clinical presentation of IDRs and noting implicated drugs, limited research has focused on the mechanisms preceding the manifestations of these severe responses. Therefore, we propose that to address the knowledge gap between drug administration and onset of a severe IDR, more research is required to understand IDR-initiating mechanisms; namely, the role of the innate immune response. In this review, we outline the immune processes involved from neoantigen formation to the result of the formation of the immunologic synapse and suggest that this framework be applied to IDR research. Using four drugs associated with severe IDRs as examples (amoxicillin, amodiaquine, clozapine, and nevirapine), we also summarize clinical and animal model data that are supportive of an early innate immune response. Finally, we discuss how understanding the early steps in innate immune activation in the development of an adaptive IDR will be fundamental in risk assessment during drug development. SIGNIFICANCE STATEMENT: Although there is some understanding that certain adaptive immune mechanisms are involved in the development of idiosyncratic drug reactions, the early phase of these immune responses remains largely uncharacterized. The presented framework refocuses the investigation of IDR pathogenesis from severe clinical manifestations to the initiating innate immune mechanisms that, in contrast, may be quite mild or clinically silent. A comprehensive understanding of these early influences on IDR onset is crucial for accurate risk prediction, IDR prevention, and therapeutic intervention.

Skin eruptions in children: Drug hypersensitivity vs viral exanthema

Childhood rashes or exanthemas are common and are usually relatively benign. There are many causes of rash in children, including mainly viruses, and less often bacterial toxins, drugs, allergens and other diseases. Viral exanthema often appears while children are taking a medication in the course of a viral infection; it can mimic drug exanthema and is perceived as a drug allergy in 10% of cases. In the vast majority of cases, the distinction between virus-induced and drug-induced skin eruption during the acute phase is not possible. The drugs most commonly implicated are beta-lactams (BL) and non-steroidal anti-inflammatory drugs (NSAIDs). Viruses, commonly Epstein-Barr virus (EBV), human herpesvirus 6 (HHV6) and cytomegalovirus (CMV), and the bacterium, Mycoplasma pneumoniae, may cause exanthema either from the infection itself (active or latent) or because of interaction with drugs that are taken simultaneously. Determination of the exact diagnosis requires a careful clinical history and thorough physical examination. Haematological and biochemical investigations and histology are not always helpful in differentiating between the two types of exanthema. Serological and polymerase chain reaction (PCR) assays can be helpful, although a concomitant acute infection does not exclude drug hypersensitivity. A drug provocation test (DPT) is although considered the gold standard for the diagnosis and is not preferred by the patients. Skin tests are not well tolerated, and in vitro tests, such as the basophil activation test and lymphocyte transformation, are of low sensitivity and specificity and their relevance is debatable. Based on current evidence, we propose a systematic clinical approach for timely differential diagnosis and management of rashes in children who present a cutaneous eruption while receiving a drug.

Eosinophils in skin diseases

Eosinophil infiltration is a common finding in a broad spectrum of skin diseases, despite the fact that the skin is devoid of eosinophils under physiologic conditions. Although cutaneous eosinophilia is reactive, cytokine-mediated in most cases, diseases with an intrinsic mutation-mediated clonal expansion of eosinophils can also manifest on the skin. As eosinophils are involved in host defense, regulate immune responses, generate pruritus, induce remodeling and fibrosis, and can cause tissue damage, they have the capacity to actively contribute to the pathogenesis of diseases. Recent research provided deeper insights in the mechanisms, e.g., bacterial and viral clearance, blister formation, recruitment of cytotoxic T cells, and generation of pruritus, by which eosinophils might come into action. This review aims at providing an overview on the clinical presentations of eosinophil-associated dermatoses and the current understanding of their pathogenic role in these diseases. Further, we discuss the effects of therapies targeting eosinophils.

Discriminating minor and major forms of drug reaction with eosinophilia and systemic symptoms: Facial edema aligns to the severe phenotype

BACKGROUND

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a cutaneous and systemic drug allergy disorder. Patients exist on a severity spectrum, with some experiencing a mild form of the disorder that fails to meet the Registry of Severe Cutaneous Adverse Reactions (SCAR) to Drugs diagnostic criteria for DRESS.

OBJECTIVE

We sought to determine whether there were any cutaneous or dermatopathologic features that discriminate between the mild form of DRESS (DRESS minor) and the severe phenotype (DRESS major).

METHODS

Hospitalized patients from a single center with a diagnosis of DRESS were prospectively recruited over a 7-year period. Clinical and dermatopathologic features were analyzed to discriminate between DRESS minor and DRESS major.

RESULTS

Forty-five patients were included, of whom 19 had a Registry of Severe Cutaneous Adverse Reactions (SCAR) to Drugs score of ≤3 (DRESS minor) and 26 had a score of ≥4 (DRESS major). The mean latency period (P = .001), fever >38.5 °C (P = .001), and a reaction lasting >15 days (P = .010) discriminated DRESS major from DRESS minor. Facial edema was the sole discerning cutaneous feature (P = .025). Discriminating histopathologic features included basal squamatization (P = .005), dermal red blood cell extravasation (P = .009), and interface inflammation (P = .005).

CONCLUSION

We propose a new classification system-DRESS minor-to distinguish the milder illness from the severe form, DRESS major. Facial edema and certain histopathologic features can help discriminate between major and minor versions.

An Uncommon Presentation of DRESS Syndrome Secondary to Leflunomide Use: A Case Report

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a constellation of symptoms that manifest as a result of certain medications. Several antipsychotics, antibiotics, and sulfa-containing drugs are known to be implicated in the etiology of DRESS syndrome. The clinical presentation of this disorder consists of a diffuse rash, lymphadenopathy, and systemic organ damage. Our patient presented with symptoms consistent with DRESS syndrome after being started on leflunomide, which is not commonly associated with DRESS. The diagnostic workup comprised of monitoring inflammatory markers on laboratory work, an excisional lymph node biopsy (to rule out malignancy), and a skin biopsy (to assess the etiology of the rash). Our patient received systemic steroids, dose-adjusted based on expert opinion. Further research is required to explore the association between leflunomide and DRESS and address guidelines for the management of DRESS.

Histopathological Spectrum and Immunophenotypic Characterization of Symmetrical Drug-Related Intertriginous and Flexural Exanthema

INTRODUCTION

Symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) is a clinically very well-defined drug eruption, but the histopathological findings are still considered to be nonspecific.

OBJECTIVES

To characterize the histopathological and immunophenotypical features of SDRIFE.

MATERIAL AND METHODS

We performed a retrospective study that identified 11 biopsies from 9 patients with SDRIFE. The histopathological features were analyzed in conjunction with the immunohistochemical findings.

RESULTS

The most common histopathological feature was basal cell vacuolization, which was often associated with necrotic keratinocytes and focal spongiosis. TIA1+ T cells and neutrophils were frequently detected in the epidermis and at the dermoepidermal junction. The dermal inflammatory infiltrate was mixed, consisting of CD3+ T cells, macrophages, granulocytes, low numbers of CD20+ B cells, and plasma cells. A combination of histopathological patterns was observed in 5 cases. The most frequent combined histopathological patterns were interface dermatitis, spongiotic dermatitis, and psoriasiform dermatitis. Other histopathological patterns found in different combinations were pustular dermatitis, perivascular and interstitial neutrophilic dermatitis, and interstitial granulomatous dermatitis. In the other 4 cases, a single histopathological pattern predominated, such as psoriasiform dermatitis, vacuolar interface dermatitis of erythema multiforme-like type, or superficial and deep perivascular and interstitial dermatitis with eosinophils and neutrophils.

CONCLUSIONS

SDRIFE is characterized histologically by a vacuolar interface dermatitis induced by cytotoxic T lymphocytes and neutrophilic granulocytes. This pattern may be obscured by accompanying spongiotic, psoriasiform, or pustular features combined with a mixed superficial and sometimes deep dermal infiltrate.

Drug reaction with eosinophilia and systemic symptoms syndrome secondary to acetazolamide associated with markedly elevated procalcitonin

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is an important cause of multi-organ dysfunction and can mimic other disorders including sepsis. We describe a patient presenting with septic shock and accompanying high procalcitonin. Although initially treated empirically with antibiotics, the emergence of eosinophilia during the admission lead to a revised diagnosis of DRESS syndrome, presumed secondary to acetazolamide. This case highlights the importance of regular clinical assessment and re-evaluation is key in identifying emerging features such as eosinophilia, rash and organ dysfunction, which can secure the diagnosis. Furthermore, the case also highlights that acetazolamide may be a rare cause of DRESS syndrome.

Updates and Insights in the Diagnosis and Management of DRESS Syndrome

PURPOSE OF REVIEW

To provide updates on recent advances in the diagnosis and management of drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome.

RECENT FINDINGS

The number of identified HLA allele associations with DRESS continues to grow. There is increasing evidence indicating viral infection, reactivation, and cross-reactivity may play key roles in disease. Translational work illuminated JAK/STAT activation in recalcitrant disease. There is expanding recognition of rapid-onset DRESS resulting from specific drugs.

SUMMARY

DRESS is a severe form of adverse drug reaction with potential for significant morbidity and mortality. Recent research advances may improve clinical care. HLA screening can now be performed to prevent disease in susceptible patients and may help identify culprit drugs in the near future. Viral testing should be performed on every patient, and if positive, patients potentially treated with antiviral therapy. JAK inhibitors may be an effective treatment option for DRESS. Early onset of disease relative to drug exposure should not exclude the diagnosis of DRESS.

The Role of Frozen Section in the Rapid Diagnosis of Severe Cutaneous Adverse Drug Reactions

CONTEXT

Early diagnosis is the mainstay in the management of severe cutaneous adverse reactions (SCARs) to drugs.

AIMS

To study the role of frozen section in the rapid diagnosis of SCARs and the impact on outcome of the affected patients.

SETTINGS AND DESIGN

A single-blind, hospital-based study was conducted from December 2014-July 2016.

METHODS AND MATERIAL

We biopsied 32 adults with SCARs diagnosed by clinical features and standard criteria. The histopathological features seen on frozen sections were compared to that of paraffin blocks. The impact of rapid diagnosis on the clinical outcome was studied in toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), drug rash with eosinophilia and systemic symptoms (DRESS) and acute generalized exanthematous pustulosis (AGEP).

STATISTICAL ANALYSIS

Z test was used to compare two proportions. Kappa statistic, sensitivity, specificity, positive predictive value, and negative predictive value of the frozen section diagnosis were calculated in TEN/SJS and DRESS using MedCalc software.

RESULTS

Frozen and paraffin sections were done in TEN/SJS spectrum (13), DRESS (17), and AGEP (2). The sensitivity, specificity and kappa values for frozen section diagnosis in SJS/TEN and DRESS were 91.7%, 95%, 0.867 and 94.4%, 100%, 0.937 respectively. The concordance between frozen and paraffin section diagnosis was 100% in TEN, SJS, DRESS and AGEP. All the 6 patients with TEN and 2 with AGEP survived. Taking the worst-case scenario, the mortality in SJS was 28.6%. The mortality among patients with DRESS was 11.8%.

CONCLUSIONS

Frozen section helps in the rapid diagnosis and early treatment of SCARs and differentiates it from diseases that mimic it.

Potentially life‑threatening severe cutaneous adverse reactions associated with tyrosine kinase inhibitors (Review)

Tyrosine kinase inhibitors (TKIs) have emerged as a new frontier of cancer therapy. These agents include inhibitors of epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), BRAF, mitogen‑activated protein kinase kinase (also referred to as MEK), bcr‑abl, c‑KIT, platelet‑derived growth factor (PDGFR), fibroblast growth factor receptor (FGFR), anaplastic lymphoma kinase (ALK) and vascular endothelial growth factor (VEGF). Along with the evolving applications of TKIs, there has been an increased recognition of the breadth of potential cutaneous toxicities to these agents. In this review, we provide an overview of potentially life‑threatening severe cutaneous adverse reactions (SCARs) that may occur during therapy with TKIs. These toxicities include Stevens‑Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP).

Gene expression profiling in allopurinol-induced severe cutaneous adverse reactions in Vietnamese

Aim: To examine gene expression in different clinical phenotypes of allopurinol-induced severe cutaneous adverse reactions (SCARs). Materials & methods: Gene expression profiling was performed using microarray on 11 RNA samples (four controls, three hypersensitivity syndrome/drug rash with eosinophilia and systemic symptoms, four Stevens-Johnson syndrome/toxic epidermal necrolysis) followed by quantitative real-time PCR in a total of 11 SCARs patients and 11 controls. Results: The biological pathways which were significantly enriched in differentially expressed genes in Stevens-Johnson syndrome/toxic epidermal necrolysis compared with hypersensitivity syndrome/drug rash with eosinophilia and systemic symptoms patients included; cell surface interactions at the vascular wall, immunoregulatory interactions at the immunological synapse and MyD88 signaling pathways. Overexpression of miR146a occurred in allopurinol-tolerant HLA-B*58:01 carriers. Conclusion: Biological pathways are identified which appear to be implicated in determining clinical phenotypes in allopurinol-induced SCARs. Overexpression of miR146a is potentially important for allopurinol tolerance in HLA-B*58:01 carriers.

Eosinophilic Dermatoses: Recognition and Management

Eosinophilic dermatoses encompass a broad spectrum of diseases of different etiologies hallmarked by eosinophilic infiltration of the skin and/or mucous membranes, with or without associated blood eosinophilia. The wide range of dermatological manifestations of this spectrum, including nodules and plaques, pustules, blisters, ulcers, and urticarial lesions, is reflected in a non-univocal classification system. We identified six groups of eosinophilic dermatoses based on the predominant anatomic level of involvement: (1) epidermal; (2) of the dermal-epidermal junction; (3) dermal; (4) of the hypodermis and muscle fascia; (5) of the pilosebaceous unit; and (6) vascular/perivascular. We review clinicopathologic features and management of diseases belonging to each group, particularly: (1) pemphigus herpetiformis and atopic dermatitis as prototypes of the epidermal group; (2) bullous pemphigoid as prototypic eosinophilic dermatosis of the dermal-epidermal junction; (3) eosinophilic cellulitis (Wells syndrome), hypereosinophilic syndromes, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome, eosinophilic dermatosis of hematologic malignancy and chronic spontaneous urticaria as paradigmatic dermal eosinophilic dermatoses; (4) eosinophilic fasciitis as an eosinophilic dermatosis with predominant involvement of the hypodermis and muscle fascia; (5) eosinophilic pustular folliculitis as a model of the pilosebaceous unit involvement; and (6) granuloma faciale, angiolymphoid hyperplasia with eosinophilia, and eosinophilic granulomatosis with polyangiitis, belonging to the vascular/perivascular group.