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.

A Systematic Review of Sodium Disorders in HHV-6 Encephalitis

Human herpesvirus 6 (HHV-6) encephalitis has a high mortality rate. Among those who survive, ~80% develop some type of permanent neurologic disorder. Early diagnosis and treatment may help prevent long-term sequelae. There have been several case reports as well as retrospective and prospective studies associating HHV-6 encephalitis with some form of sodium imbalance, either hyponatremia or hypernatremia; however, the exact frequency post-HCT is unknown, with reports ranging from 30% to 100%. We performed a systematic review of the literature and found 34 cases of HHV-6 encephalitis reported in conjunction with sodium imbalance that documented the timing of that imbalance relative to the onset of encephalitis. Sodium imbalance occurred before or at the onset of HHV-6 encephalitis in all but 2 cases (94%). This finding supports previous suggestions that sodium imbalance can be considered an early indicator of the potential development or presence of HHV-6 encephalitis in at-risk patient populations.

Clinical Phenotypes of Severe Cutaneous Drug Hypersensitivity Reactions

Drug hypersensitivity reactions are clinically heterogenous ranging from mild to severe. Most drug hypersensitivity reactions are accompanied by cutaneous manifestations. Fever, mucous membrane involvement, large blisters, facial oedema, pustulosis and visceral involvement are clinical features that lead to suspicion of severe adverse drug reactions. Severe cutaneous adverse drug reactions (SCARs) include Stevens-Johnson syndrome, toxic epidermal necrolysis, drug rash eosinophilia and systemic symptoms, acute generalized exanthematous pustulosis. Serum sickness like reactions, drug induced vasculitis and generalized bullous fixed drug eruptions are less severe clinical entities. SCARs are uncommon but associated with significant morbidity and mortality. Physician should be aware of specific red flags and danger signs to immediately identify these reactions. Immediate drug withdrawal is mandatory. Early diagnosis and appropriate treatment significantly affect the prognosis of the disease. The purpose of our review is to discuss clinical phenotypes of severe cutaneous drug hypersensitivity reactions.

A case of drug-induced hypersensitivity syndrome induced by salazosulfapyridine combined with SIADH caused by interstitial pneumonia

We present a case of a patient with drug-induced hypersensitivity syndrome (DIHS) caused by salazosulfapyridine combined with syndrome of inappropriate secretion of antidiuretic hormone (SIADH) caused by interstitial pneumonia (IP). A 67-year-old man with a past history of rheumatism (RA) presented with right hemiparalysis and aphasia as the chief complaints. A diagnosis of left embolic cerebral infarction following trial therapy for RA based on computed tomography findings was made, and external decompression was performed. Salazosulfapyridine was newly started on day 7. Dabigatran was started on day 37. On day 41, the patient developed fever. On day 42, edema and erythema appeared on his face, and erythema and rash appeared on his trunk and extremities, with gradual transition to erythroderma. The drug eruption was initially attributed to the dabigatran. Various symptoms of organ dysfunction (enteritis, myocarditis, interstitial pneumonia, hepatic disorder, stomatitis, and others) then appeared and persisted; hence, a diagnosis of DIHS associated with human herpes virus 6 and cytomegalovirus infection induced by salazosulfapyridine was suggested, and the oral administration of salazosulfapyridine was discontinued on day 53. Hyponatremia was observed in association with exacerbation of IP. Due to low serum osmotic pressure and prompt improvement of the serum sodium level by fluid restriction, the SIADH was attributed to IP. In this case, steroid pulse therapy followed by gradual decrease therapy prevented worsening of the condition.

Autoimmune Limbic Encephalitis and Syndrome of Inappropriate Antidiuretic Hormone Secretion Associated with Lamotrigine-induced Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) Syndrome

Drug rash with eosinophilia and systemic symptoms (DRESS) is a severe drug hypersensitivity reaction characterized by rash, fever and multi-organ failure. Limbic encephalitis (LE) is a rare disorder characterized by cognitive dysfunction with memory disturbance, seizures and psychiatric symptoms. We herein present an unusual case of DRESS syndrome due to lamotrigine with reactivation of Epstein-Barr virus, which developed autoimmune LE and syndrome of inappropriate antidiuretic hormone secretion. Discontinuation of lamotrigine, administration of methylprednisolone and intravenous immunoglobulin led to improvement. The LE in this case might have been caused by an autoimmune inflammatory mechanism associated with DRESS syndrome.

Considerations regarding the management of hyponatraemia secondary to SIADH

Treatment of hyponatraemia secondary to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) should be guided by the symptomatology of the patient, which can be used as a surrogate for the duration of the hyponatraemia. However, in patients with acute symptomatic hyponatraemia (developing in <48 hours), the need to actively treat hyponatraemia is more imperative due to the potential risks associated with leaving hyponatraemia untreated (including the potential for development of serious neurological manifestations, such as seizures and brain stem herniation). In patients with hyponatraemia care needs to be taken not to exceed the recommended rates of correction, as this increases the risk of osmotic demyelination syndrome. This article will discuss the potential impact of prompt intervention in the treatment of hyponatraemia, particularly secondary to SIADH, and the need to weigh the benefits of treatment against the potential risks associated with overly rapid correction.

The DRESS syndrome: a literature review

The Drug Reaction with Eosinophilia and Systemic Symptom (DRESS) is a severe adverse drug-induced reaction. Diagnosing DRESS is challenging due to the diversity of cutaneous eruption and organs involved. We used the RegiSCAR scoring system that grades DRESS cases as "no," "possible," "probable," or "definite" to classify cases reported in the literature. We also analyzed the clinical course and treatments of the cases. A total of 44 drugs were associated with the 172 cases reported between January 1997 and May 2009 in PubMed and MEDLINE. The most frequently reported drug was carbamazepine, and the vast majority of cases were classified as "probable/definite" DRESS cases. Hypereosinophilia, liver involvement, fever, and lymphadenopathy were significantly associated with "probable/definite" DRESS cases, whereas skin rash was described in almost all of the cases, including "possible cases." Culprit drug withdrawal and corticosteroids constituted the mainstay of DRESS treatment. The outcome was death in 9 cases. However, no predictive factors for serious cases were found. This better knowledge of DRESS may contribute to improve the diagnosis and management of this syndrome in clinical practice.

[Auto-immune thyroiditis and drug reaction with eosinophilia and systemic symptoms (DRESS) associated with HHV-6 viral reactivation]

INTRODUCTION

DRESS syndrome is a severe adverse drug reaction with visceral involvement. Its physiopathology includes immunological disorders associated with human herpes virus (HHV) reactivation. We report two cases of auto-immune thyroiditis occurring in the context of DRESS syndrome associated with HHV-6 reactivation.

OBSERVATIONS

Case 1 : A 39-year-old woman presented DRESS syndrome with HHV-6 reactivation, cutaneous, lymph node, hepatic and renal disorders treated with systemic corticosteroids for 10 months. Following discontinuation of the corticosteroids, she developed Graves's disease, which was stabilized with carbimazole and a beta-blocker. CASE 2: A 31-year-old woman was hospitalized for DRESS syndrome with delayed HHV-6 reactivation and severe hepatic involvement. She was successfully treated by topical steroids. Six weeks later, she presented De Quervain thyroiditis associated with moderate relapsing DRESS, which were treated by sodium levothyroxine and topical steroids.

DISCUSSION

There is currently debate about the implication of viral reactivation, in particular HHV-6, in chronic DRESS, relapse and development of auto-immune diseases. These observations highlight the potential risk of patients developing auto-immune diseases and underline the need for prolonged clinical and laboratory follow-up of patients with DRESS.

Fatal encephalitis in a case of hypereosinophilic syndrome: MRI and autopsy findings

A 34-year-old man developed fever and headache, followed by finger tremor and gait disturbance, and was admitted to our hospital about two months after onset. Blood tests showed a white blood cell count of 32,600 /µL with an eosinophil count of 22,300 /µL. There was no evidence of allergic drug reaction or parasitic infection. Cerebrospinal fluid examination demonstrated mononuclear pleocytosis without eosinophils or atypical cells. Brain MRI showed symmetric lesions bilaterally in the medial temporal lobe, frontobasal and insular regions and medulla oblongata. Herpes simplex virus-DNA was negative in the cerebrospinal fluid. The patient died about four months after onset. Histopathologically, there was infiltration of T cells, B cells and macrophages throughout the whole brain, but eosinophils or atypical cells were absent. Immunohistochemistry for herpes simplex virus type 1 and human herpesvirus 6 was negative. This case suggests that fatal encephalitis may develop in association with hypereosinophilic syndrome.

Recognition of immune reconstitution syndrome necessary for better management of patients with severe drug eruptions and those under immunosuppressive therapy

The immune reconstitution syndrome (IRS) is an increasingly recognized disease concept and is observed with a broad-spectrum of immunosuppressive therapy-related opportunistic infectious diseases and severe drug eruptions complicated by viral reactivations. Clinical illness consistent with IRS includes tuberculosis, herpes zoster, herpes simples, cytomegalovirus infections and sarcoidosis: thus, the manifestations of this syndrome and diverse and depend on the tissue burden of the preexisting infectious agents during the immunosuppressive state, the nature of the immune system being restored, and underlying diseases of the hosts. Although IRS has originally been reported to occur in the setting of HIV infection, it has become clear that the development of IRS can also be in HIV-negative hosts receiving immunosuppressive agents, such as prednisolone and tumor necrosis factor α inhibitors, upon their reduction and withdrawal. Drug-induced hypersensitivity syndrome, a life-threatening multiorgan system reaction, is another manifestation of the newly observed IRS. Clinical recognition of the IRS is especially important in improving the outcome for diseases with an otherwise life-threatening progenosis. Clinicians should be aware of the implications of IRS and recognize that relieving the symptoms and signs of immune recovery by anti-inflammatory therapies needs to be balanced with anti-microbial therapies aiming at reducing the amplitude and duration of tissue burden of preexisting microbes.

Visceral involvements and long-term sequelae in drug-induced hypersensitivity syndrome

Drug-induced hypersensitivity syndrome (DIHS) is a severe systemic reaction with several herpesvirus reactivations. Multiple organ failures appear during the course of the disease. The severity of DIHS is determined by the degree of visceral involvement. Autoimmune diseases also develop several months to years after the apparent clinical resolution of DIHS.

Is the drug-induced hypersensitivity syndrome (DIHS) due to human herpesvirus 6 infection or to allergy-mediated viral reactivation? Report of a case and literature review

Background

Drug-Induced Hypersensitivity Syndrome (DIHS) is a severe and rare systemic reaction triggered by a drug (usually an antiepileptic drug). We present a case of DISH and we review studies on the clinical features and treatment of DIHS, and on its pathogenesis in which two elements (Herpesvirus infection and the drug) interact with the immune system to trigger such a syndrome that can lead to death in about 20% of cases.

Case presentation

We report the case of a 26-year old woman with fever, systemic maculopapular rash, lymphadenopathy, hepatitis and eosinophilic leukocytosis. She had been treated with antibiotics that gave no benefit. She was taking escitalopram and lamotrigine for a bipolar disease 30 days before fever onset. Because the patient's general condition deteriorated, betamethasone and acyclovir were started. This treatment resulted in a mild improvement of symptoms. Steroids were rapidly tapered and this was followed with a relapse of fever and a worsening of laboratory parameters. Human herpesvirus 6 (HHV-6) DNA was positive as shown by PCR. Drug-Induced Hypersensitivity Syndrome (DIHS) was diagnosed. Symptoms regressed on prednisone (at a dose of 50 mg/die) that was tapered very slowly. The patient recovered completely.

Conclusions

The search for rare causes of fever led to complete resolution of a very difficult case. As DIHS is a rare disease the most relevant issue is to suspect and include it in differential diagnosis of fevers of unknown origin. Once diagnosed, the therapy is easy (steroidal administration) and often successful. However our case strongly confirms that attention should be paid on the steroidal tapering that should be very slow to avoid a relapse.

The variable clinical picture of drug-induced hypersensitivity syndrome/drug rash with eosinophilia and systemic symptoms in relation to the eliciting drug

Drug-induced hypersensitivity syndrome (DIHS)/drug rash with eosinophilia and systemic symptoms (DRESS) is a life-threatening adverse reaction characterized by skin rashes, fever, leukocytosis with eosinophilia or atypical lymphocytosis, lymph node enlargement, and liver or renal dysfunction. The syndrome develops 2 to 6 weeks after initiation of administration of a specific drug. It has been demonstrated that various herpesvirus reactivations, in addition to human herpesvirus 6, contribute to internal organ involvement and the relapse of symptoms observed long after discontinuation of the causative drugs. A better understanding of the interplay in the development of DIHS/DRESS has implications for safer and more efficient treatment of this syndrome.

Viral connection between drug rashes and autoimmune diseases: how autoimmune responses are generated after resolution of drug rashes

Viral infections are most likely triggering factors of autoimmune diseases, although a single vial infection is not sufficient to cause clinically evident autoimmune diseases. Any disease that profoundly alters the immune system may cause perturbed viral infections, thereby rendering otherwise refractory patients susceptible to autoimmune diseases. In this regard, drug-induced hypersensitivity syndrome (DIHS), a drug rash characterized by sequential reactivations of herpesviruses and the subsequent development of autoimmune diseases, offers a unique opportunity to investigate the mechanism of how autoimmunity is elicited after viral infections. Indeed, several autoimmune diseases have been reported to occur at intervals of several months to years after clinical resolution of DIHS. Two representative cases who developed autoimmune diseases three to four years after DIHS are shown. Our recent analyses of the kinetics of a developing disease have shown that fully functional FoxP3(+) regulatory T (Treg) cells are expanded at the acute stage thereby allowing viral reactivations but lose their suppressive function coincident with their contraction upon clinical resolution. The functional defect of Treg cells would be responsible for the subsequent development of autoimmune diseases. Patients with DIHS need close monitoring because of possible progression to autoimmune diseases even after the complete resolution.