Cutaneous Manifestation of Drug Allergy and Hypersensitivity

The role of the environment in allergic skin disease

PURPOSE OF REVIEW

This paper explores how environmental factors influence allergic skin diseases, including atopic dermatitis (AD), contact dermatitis (CD), urticaria, angioedema, and reactions to drugs and insect bites.

RECENT FINDINGS

Research indicates a significant impact of environmental elements on allergic skin diseases. High air pollution levels exacerbate symptoms, while climate change contributes to increased skin barrier dysfunction, particularly affecting AD. Allergen prevalence is influenced by climate and pollution. Irritants, like those in detergents and cosmetics, play a major role in CD. Plants also contribute, causing various skin reactions. Understanding the interplay between environmental factors and allergic skin diseases is crucial for effective management. Physicians must address these factors to support patient well-being and promote skin health amidst environmental changes.

Immunological Mechanisms in Cutaneous Adverse Drug Reactions

Adverse drug reactions (ADRs) are an inherent aspect of drug use. While approximately 80% of ADRs are predictable, immune system-mediated ADRs, often unpredictable, are a noteworthy subset. Skin-related ADRs, in particular, are frequently unpredictable. However, the wide spectrum of skin manifestations poses a formidable diagnostic challenge. Comprehending the pathomechanisms underlying ADRs is essential for accurate diagnosis and effective management. The skin, being an active immune organ, plays a pivotal role in ADRs, although the precise cutaneous immunological mechanisms remain elusive. Fortunately, clinical manifestations of skin-related ADRs, irrespective of their severity, are frequently rooted in immunological processes. A comprehensive grasp of ADR morphology can aid in diagnosis. With the continuous development of new pharmaceuticals, it is noteworthy that certain drugs including immune checkpoint inhibitors have gained notoriety for their association with ADRs. This paper offers an overview of immunological mechanisms involved in cutaneous ADRs with a focus on clinical features and frequently implicated drugs.

Diseases from the Spectrum of Dermatitis and Eczema: Can "Omics" Sciences Help with Better Systematics and More Accurate Differential Diagnosis?

Researchers active in the field of inflammatory skin diseases from the spectrum of dermatitis and eczema are well aware of a considerable overlap in the clinical pictures and proposed sets of diagnostic criteria for these diseases, which can hardly be overcome through the clinical or epidemiological research. In effect, patients are included in studies based on vague and overlapping criteria, while heterogeneous study populations may, in turn, lead to non-representative outcomes and continued confusion. In this narrative review, a systematics of diseases from the spectrum of dermatitis and eczema is proposed based on the origins of causative factors and the pathomechanisms involved. Difficulties in differentiating between these diseases are discussed, and the extent to which advances in the "omics" sciences might help to overcome them is considered. Of all the "omics" research in this field, more than 90% of the published papers were devoted to atopic dermatitis, with a striking underrepresentation of other diseases from the spectrum of dermatitis and eczema, conditions which collectively exceed the rates of atopic dermatitis by far. A greater "omics" research effort is urgently needed to tackle other dermatitides, like allergic, irritant and protein contact dermatitis, as well as radiation, seborrheic, stasis or autoimmune dermatitis. Atopic dermatitis findings should be validated not only against healthy donors but also other dermatitides. A clinic-oriented approach is proposed for future "omics" studies in the field of dermatitis and eczema.

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS): Focus on the Pathophysiological and Diagnostic Role of Viruses

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a heterogeneous, multiorgan and potentially life-threatening drug-hypersensitivity reaction (DHR) that occurs several days or weeks after drug initiation or discontinuation. DHRs constitute an emerging issue for public health, due to population aging, growing multi-organ morbidity, and subsequent enhanced drug prescriptions. DRESS has more consistently been associated with anticonvulsants, allopurinol and antibiotics, such as sulphonamides and vancomycin, although new drugs are increasingly reported as culprit agents. Reactivation of latent infectious agents such as viruses (especially Herpesviridae) plays a key role in prompting and sustaining aberrant T-cell and eosinophil responses to drugs and pathogens, ultimately causing organ damage. However, the boundaries of the impact of viral agents in the pathophysiology of DRESS are still ill-defined. Along with growing awareness of the multifaceted aspects of immune perturbation caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the ongoing SARS-CoV-2-related disease (COVID-19) pandemic, novel interest has been sparked towards DRESS and the potential interactions among antiviral and anti-drug inflammatory responses. In this review, we summarised the most recent evidence on pathophysiological mechanisms, diagnostic approaches, and clinical management of DRESS with the aim of increasing awareness on this syndrome and possibly suggesting clues for future research in this field.

Severe Cutaneous Adverse Drug Reactions at a Tertiary Care Center in Saudi Arabia

Background

Severe cutaneous adverse drug reactions (SCARs), although rare, are known to be associated with significant morbidity and mortality. SCARs include drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), and acute generalized exanthematous pustulosis (AGEP). Studies on SCARs are limited in Saudi Arabia. This study aims to characterize SCARs at a tertiary care center in Saudi Arabia.

Methods

A cross-sectional study was conducted at King Abdulaziz Medical City, Riyadh, Saudi Arabia. All inpatient and emergency department consultations to dermatology were electronically reviewed during the period from January 2016 to December 2020. All patients who developed an adverse cutaneous drug reaction were enrolled. Detailed analysis was performed only for SCARs. The culprit medication was determined based on the latency period, history of previous intake of the medication, and drug notoriety.

Results

There were 3050 hospital consultations to dermatology during the study period. Cutaneous adverse drug reactions constituted 253 (8.3%) cases. A total of 41 patients with SCARs were identified, accounting for 16.2% of all cutaneous drug reactions. Antibiotics and anticonvulsants were the most common causative drug groups accounting for 28 (68.3%) and 9 (22%) cases, respectively. DRESS was the most common SCAR. The latency period was the longest for DRESS and shortest for AGEP. Vancomycin was responsible for approximately a third of DRESS cases. Piperacillin/tazobactam was the most common cause for SJS/TEN and AGEP. The majority of drugs causing AGEP were antibiotics. The mortality rate was the highest in SJS/TEN (5/11 (45.5%)), followed by DRESS (1/23 (4.4%)) and AGEP (1/7 (14.3%)).

Conclusion

SCARs are rare in Saudis. DRESS appears to be the most common SCAR in our region. Vancomycin is responsible for most cases of DRESS. SJS/TEN had the highest mortality rate. More studies are required to further characterize SCARs in Saudi Arabia and Arabian Gulf countries. More importantly, thorough studies of HLA associations and lymphocyte transformation tests among Arabs with SCARs are likely to further improve patient care in the Arabian Gulf region.

Quality of Life for Children with Allergic Skin Diseases

Allergic skin diseases are highly prevalent among children. Patients with allergic skin diseases experience sociopsychological and quality-of-life (QoL) burdens in excess of those in the general population. Children and their caregivers are especially vulnerable to the burden of many of the common allergic skin diseases. In the past few decades, researchers have developed a number of disease-specific scores and indices for the measurement of QoL for childhood skin diseases. Most of the research in this area has focused on atopic eczema and urticaria and less so on allergic contact dermatitis. We provide an overview of QoL and its assessment for these dermatologic conditions.

Drug hapten-specific T-cell activation: Current status and unanswered questions

Drug haptens are formed from the irreversible, covalent binding of drugs to nucleophilic moieties on proteins, which can warrant adverse reactions in the body including severe delayed-type, T-cell mediated, drug hypersensitivity reactions (DHRs). While three main pathways exist for the activation of T-cells in DHRs, namely the hapten model, the pharmacological interaction model and the altered peptide repertoire model, the exact antigenic determinants responsible have not yet been defined. In recent years, progress has been made using advanced mass spectrometry-based proteomic methods to identify protein carriers and characterise the structure of drug-haptenated proteins. Since genome-wide association studies discovered a link between human leukocyte antigens (HLA) and an individual's susceptibility to DHRs, much effort has been made to define the drug-associated HLA ligands driving T-cell activation, including the elution of natural HLA peptides from HLA molecules and the generation of HLA-binding peptides. In this review, we discuss our current methodology used to design and synthesise drug-modified HLA ligands to investigate their immunogenicity using T-cell models, and thus their implication in drug hypersensitivity.

Drug-Induced Skin Adverse Reactions: The Role of Pharmacogenomics in Their Prevention

Adverse drug reactions (ADRs) affect many patients and remain a major public health problem, as they are a common cause of morbidity and mortality. It is estimated that ADRs are responsible for about 6% of hospital admissions and about 9% of hospitalization costs. Skin is the organ that is most frequently involved in ADRs. Drug-induced skin injuries vary from mild maculopapular eruptions (MPE) to severe cutaneous adverse reactions (SCARs) that are potentially life threatening. Genetic factors have been suggested to contribute to these SCARs, and most significant genetic associations have been identified in the major histocompatibility complex (MHC) genes. Common drugs associated with SCARs connected with strong genetic risk factors include antiepileptic drugs (AEDs), allopurinol, abacavir, nevirapine, sulfonamides, dapsone, non-steroidal anti-inflammatory drugs (NSAIDs), and analgesic drugs. However, genetic associations vary between different ethnic populations. Differences may in part be explained by the different prevalence of HLA (human leukocyte antigen) alleles among ethnic groups. In this review, we present and discuss the recent advances in genetic associations with ADRs in the skin. Many of these ADRs are now preventable with pharmacogenetic screening.

Sulfonamide Drug Allergy

PURPOSE OF REVIEW

We sought to review past and current literature on sulfonamide drug allergy and distill it in a practical manner to assist the clinician, specifically focusing on cross-reactivity and desensitization.

RECENT FINDINGS

There do not appear to be consistent genetic markers to reliably predict features of or the presence hypersensitivity reactions. Recent evidence continues to alleviate early concerns cross-reactivity between sulfonamide antibiotics and non-antibiotics. Sulfonamide drug allergy is frequently encountered by the practicing clinician. For sulfonamide antibiotics, delayed rash is the most common clinical manifestation. There is no current evidence to support avoidance of all non-antibiotic sulfonamides in those with a reported allergy to sulfonamide antibiotics, although certain scenarios require caution. Available evidence supports the cautious reintroduction of sulfonamide antibiotics via desensitization, which is usually well tolerated and should be considered in those with strong indications for trimethoprim-sulfamethoxazole and a reported sulfonamide allergy.

Treatment of severe drug reactions by hemodialysis

BACKGROUND

Extracorporeal treatments such as hemodialysis and plasma exchange are lifesaving measures in the treatment of drug poisoning. This treatment method generally is not used for severe cutaneous and systemic drug reactions.

METHODS

Here, we describe three cases wherein hemodialysis therapy was instrumental in reversing the adverse drug reaction.

RESULTS

In the cases of severe cutaneous drug reactions reviewed, patients presented with linear immunoglobulin A bullous dermatosis, acute generalized exanthematous pustulosis, and toxic epidermal necrolysis. Salvage treatment with hemodialysis therapy drastically influenced the course of disease, resulting in remission.

CONCLUSIONS

This novel and highly effective treatment option is not considered in current algorithms for adverse drug reactions. Hence, in addition to the rarity of these reactions, the main limitation of the study is the small number of patients. Hemodialysis can substantially alter the prognosis and, in some cases, be a lifesaving treatment for patients with severe adverse cutaneous drug reaction associated with systemic toxicity.