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.

Leukemoid reaction in minocycline-induced drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome: A brief report.

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is an idiosyncratic drug reaction hallmarked by cutaneous eruption, fever, lymphadenopathy, multiorgan involvement, and hematological abnormalities, most often eosinophilia and atypical lymphocytosis. Leukemoid reactions have rarely been described in DRESS syndrome and here we describe a 16-year-old male who was admitted to the hospital with DRESS syndrome due to minocycline, who had a severe leukocytosis up to 52.08 K/µL. He improved with cessation of minocycline and initiation of systemic steroids. We report this case to add to the literature on hematological abnormalities in pediatric DRESS syndrome.

DRESS/DiHS syndrome induced by Propylthiouracil: a case report.

BACKGROUND: Drug reaction with eosinophilia and systemic symptoms (DRESS), also known as Drug-induced hypersensitivity syndrome (DiHS), is a severe adverse drug reaction. Propylthiouracil, a member of thiouracils group, is widely used in medical treatment of hyperthyroidism. Propylthiouracil is associated with multiple adverse effects such as rash, agranulocytosis hepatitis and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, but rarely triggers DRESS/DiHS syndrome. Here, we describe a severe case of propylthiouracil-induced DRESS/DiHS syndrome. CASE PRESENTATION: A 38-year-old female was treated with methimazole for hyperthyroidism at first. 4 weeks later, the patient developed elevated liver transaminase so methimazole was stopped. After liver function improved in 2 weeks, medication was switched to propylthiouracil therapy. The patient subsequently developed nausea and rash followed by a high fever, acute toxic hepatitis and multiple organ dysfunction (liver, lung and heart), which lasted for 1 month after propylthiouracil was started. According to the diagnostic criteria, the patient was diagnosed of DRESS/DiHS syndrome which was induced by propylthiouracil. As a result, propylthiouracil was immediately withdrawn. And patient was then treated with adalimumab, systematic corticosteroids and plasmapheresis in sequence. Symptoms were finally resolved 4 weeks later. CONCLUSIONS: Propylthiouracil is a rare cause of the DRESS/DiHS syndrome, which typically consists of severe dermatitis and various degrees of internal organ involvement. We want to emphasize through this severe case that DRESS/DiHS syndrome should be promptly recognized to hasten recovery.

Immunopathogenic Insights on Preferential Human Herpesvirus-6 Reactivation in Drug Rash With Eosinophilia and Systemic Symptoms: A Scoping Review.

INTRODUCTION: Human herpesvirus-6 (HHV-6) is a ubiquitous lymphotropic betaherpesvirus that can reactivate in drug rash with eosinophilia and systemic symptoms (DRESS). Despite recent publications advancing our understanding of HHV-6 in DRESS, the exact role of HHV-6 in disease pathogenesis remains unclear. METHODS: A scoping review with the PubMed query "(HHV 6 AND (drug OR DRESS OR DIHS)) OR (HHV6 AND (drug OR DRESS OR DIHS))" was conducted in accordance with PRISMA guidelines. Articles containing original data on at least one DRESS patient with HHV-6 testing were included. RESULTS: Our search returned a total of 373 publications, of which 89 met eligibility criteria. HHV-6 reactivation occurred in 63% of DRESS patients (n = 748), which was significantly more often than other herpesviruses. HHV-6 reactivation was associated with worse outcomes and greater severity in controlled studies. Case reports have demonstrated sometimes fatal HHV-6-related multi-organ involvement. Temporally, HHV-6 reactivation typically occurs 2 to 4 weeks after DRESS onset and has been linked to markers of immunologic signaling, such as OX40 (CD134), an HHV-6 entry receptor. Efficacy of antiviral or immunoglobulin treatment has only been demonstrated anecdotally, and steroid use may affect HHV-6 reactivation. CONCLUSION: HHV-6 is implicated in DRESS more than in any other dermatologic condition. It is still unclear whether HHV-6 reactivation is cause or consequence of DRESS dysregulation. Similar pathogenic mechanisms precipitated by HHV-6 in other contexts may be relevant in DRESS. Future randomized controlled studies to assess effects of viral suppression on clinical outcomes is needed.

DRESS, the maverick among SCARS: A case series-based review of literature.

DRESS is a potentially life-threatening severe cutaneous adverse reaction (SCAR). Historically, it was most frequently linked with phenytoin and was initially described as phenytoin hypersensitivity syndrome; however, it was later found to be caused by various other medications, with the commonest been aromatic anticonvulsants, allopurinol and sulfonamides. The severity of this entity is related to systemic involvement, which can result in multiorgan failure and death. The diagnosis of DRESS, especially in the early stages, remains challenging and elusive due to its heterogeneous clinical presentation and the complex course of the disease with different patterns depending on the causal drug. The most important step in the management of DRESS is early diagnosis and immediate cessation of the suspected offending drug along with oral steroids or immunosuppressants to control the disease. We describe the varying presentation and management of six adults with DRESS from a tertiary care hospital, observed over a two-year period with a brief review of the literature.

Clinical features of drug-induced hypersensitivity syndrome to BRAF inhibitors with and without previous immune checkpoint inhibition: a review.

PURPOSE: Cutaneous reactions to BRAF inhibitors are common, but severe reactions resembling or consistent with drug-induced hypersensitivity syndrome (DIHS)/drug reaction with eosinophilia and systemic symptoms (DRESS) are relatively rare. Several reports suggest that cutaneous reactions including DRESS/DIHS to BRAF inhibitors are more frequent and severe in the setting of previous immune checkpoint inhibition (ICI). METHODS: To characterize existing literature on these reports, we queried the PubMed/MEDLINE database for cases of DIHS/DRESS to BRAF inhibitors. RESULTS: We identified 23 cases of DIHS to BRAF inhibitors following checkpoint inhibition and 14 cases without prior checkpoint inhibitor therapy. In both cohorts, DIHS occurred relatively early, with median time to onset from drug exposure of 8-10 days. Patients who received prior ICI were less likely to have peripheral eosinophilia (26% vs 71%), atypical lymphocytes (9% vs 50%), renal involvement (61% vs 79%), hepatic involvement (52% vs 86%), and lymphadenopathy (9% vs 43%) compared to patients who did not receive prior ICI. Thrombocytopenia was more common with prior ICI (17% vs 7%). Only patients who received prior ICI experienced hypotension (26%) during the course of their DIHS. All cases of BRAF-induced DIHS generally improved on systemic steroids/supportive care, and no cases of death were identified. CONCLUSION: Dermatologists should consider a diagnosis of DIHS following BRAF inhibitor initiation, particularly in the setting of past checkpoint inhibition, with atypical features including relatively rapid onset and steroid responsiveness, lack of peripheral eosinophilia, lymphocytosis, or lymphadenopathy, and increased risk of thrombocytopenia and hypotension.

Drug-induced hypersensitivity syndrome following temozolimide for glioblastoma multiforme and the role of desensitization therapy.

INTRODUCTION: Temozolomide is an oral alkylating agent used as first line treatment of glioblastoma multiforme (GBM). It has also been used in the treatment of certain solid tumors such as metastatic melanoma. Commonly reported adverse effects include nausea and vomiting, constipation, headache, fatigue and myelosuppression. Cutaneous hypersensitivity reactions are rare and include an urticarial hypersensitivity reaction, alopecia, and Stevens-Johnson syndrome. To our knowledge, there are minimal reports of temozolomide-induced DRESS syndrome. CASE REPORT: We present a 54-year-old man with glioblastoma multiforme who presented with a fever, diarrhea and progressively worsening rash 6 weeks after starting temozolomide. MANAGEMENT & OUTCOME: The patient was diagnosed recurrent DRESS syndrome and restarted on a gradual prednisone taper with resolution over the following weeks. Unfortunately, the patient was unable to be followed long-term due to relocation to a different state. DISCUSSION: To our knowledge, there are minimal reports of temozolomide-induced DRESS syndrome. The diagnosis can be life-threatening, which makes management of patients with GBM and no alternative treatment option challenging. The use of de-sensitization therapy to temozolomide has been proposed for the management of severe adverse cutaneous reactions.

Clinical features, treatment outcomes and prognostic factors of allopurinol-induced DRESS in 52 patients.

WHAT IS KNOWN AND OBJECTIVE: Allopurinol-induced drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare but serious and potentially life-threatening drug hypersensitivity syndrome. In this study, we aimed to investigate the clinical features, treatment outcomes, and prognostic factors of allopurinol-induced DRESS. METHODS: Case reports of allopurinol-induced DRESS published by China from January 2000 to August 2021 were retrieved from CNKI, Wan Fang, VIP, and PubMed databases for analysis. RESULTS AND DISCUSSION: This study included 52 patients, consisting of 41 (78.8%) males and 11 (21.2%) females (M:F = 3.7:1). The mean of age was 56.1 ± 17.1 years (range: 18-86 years). The mean of latency periods was 24.6 ± 15.0 days (range:1-63 days). Most patients presented with fever, cutaneous eruption, eosinophilia, lymphadenopathy, and facial edema. 36/52 (69.2%) patients showed two or more internal organs involved. Liver and kidney injuries were the most common visceral manifestation. Pulmonary involvement (34.6%), cardiac involvement (25.0%) and gastrointestinal involvement (21.2%) were relatively less known but severe complications. 2/52 (3.8%) patients showed nervous system involved, presenting as leukoencephalopathy or peripheral neuropathy. 2/52 (3.8%) patients presented with secondary hemophagocytic lymphohistiocytosis.1/52 (1.9%) patient developed pure red cell aplasia and 1/52 (1.9%) patient developed painless thyroiditis. HLA*B 58:01 allele was tested in 18/52 (34.6%) patients. 16/18 (88.9%) cases were positive. 48/52 (92.3%) patients were treated with systemic corticosteroids. 16/52 (30.8%) patients were cured, 23/52 (44.2%) patients received partial recovery, and 13/52 (25.0%) patients were died. Septic shock, gastrointestinal bleeding and multiple organ failure were the leading causes of death. Advanced age, underlying cardiovascular disease, chronic kidney disease and high dose of allopurinol, infection and internal organ involvement (including kidney, heart, lung and gastrointestinal tract) were risk factors for death. WHAT IS NEW AND CONCLUSION: We explored clinical features, treatment outcomes and prognostic factors of 52 allopurinol-induced DRESS cases in China. Ethnicity, especially Han Chinese, and positive HLA-B*58:01 allele are the clearest risk factors so far. Advanced age, underlying cardiovascular disease, chronic kidney disease and high dose of allopurinol, infection and internal organ involvement (including kidney, heart, lung and gastrointestinal tract) were associated with poorer outcomes. Early identification and discontinuation of the causative drug are crucial to the management of DRESS. For patients with severe disease, corticosteroids are recommended as the first-line therapy. However, further studies are needed to address diagnostic criteria of DRESS for early diagnosis, as well as to develop standardized corticosteroid treatment regimens.

Patch testing in drug reaction with eosinophilia and systemic symptoms (DRESS): A literature review.

The literature on positive patch test results in drug reaction with eosinophilia and systemic symptoms (DRESS) is reviewed. One hundred and five drugs were identified that have together caused 536 positive patch tests in 437 DRESS patients. By far, the most reactions (n = 145) were caused by carbamazepine, followed by amoxicillin, isoniazid, phenytoin, ethambutol, fluindione, phenobarbital, rifampicin, and ceftriaxone; 43 drugs each caused a single case only. The drug classes causing the highest number of reactions were anticonvulsants (39%), beta-lactam antibiotics (20%), antituberculosis agents (11%), non-beta-lactam antibiotics (6%), and iodinated contrast media (5%). The sensitivity of patch testing (percentage of positive reactions) is high for anticonvulsants (notably carbamazepine), beta-lactam antibiotics (notably amoxicillin), and, possibly, iodinated contrast media. Allopurinol and sulfasalazine frequently cause DRESS but never give positive patch tests. Patch testing in DRESS appears to be safe, although mild recurrence of DRESS symptoms, mostly skin reactions, may not be rare. Multiple drug hypersensitivity was found to occur in 16% of all patients, but it is argued that the true frequency is higher. Clinical aspects of DRESS, including diagnosing the disease and identifying culprit drugs (patch tests, intradermal tests, in vitro tests, challenge tests) are also provided, emphasizing the role of patch testing.

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms following nivolumab and ipilimumab in a pediatric patient with melanoma.

Drug-induced hypersensitivity syndrome (DIHS) is a type of severe cutaneous adverse reaction (SCAR). DIHS typically occurs 2-6 weeks after initiation of the offending medication. We report a case of DIHS in a pediatric patient undergoing treatment of metastatic melanoma with nivolumab and ipilimumab.

Current Understanding of Immunological Skin Diseases: Atopic Dermatitis, Generalized Anhidrosis, and Drug Hypersensitivity.

Recent dermatological research has progressed, particularly novel technologies and analytical methodologies, providing great advances in the exploration of previously poorly understood interactions between the skin-the outermost surface of humans-and the external environment [...].

Association of interleukin-6 and tumor necrosis factor-α with mortality in hospitalized patients with cancer.

BACKGROUND: Severe cutaneous adverse reactions (SCARs) are associated with high morbidity and mortality in patients with cancer. Early identification and treatment of SCARs may improve outcomes. OBJECTIVE: To identify biomarkers to predict outcomes in hospitalized patients with cancer who developed SCARs. METHODS: Retrospective review of 144 hospitalized patients with cancer with a morbilliform rash, recorded testing for serum cytokines (interleukin [IL]-6, IL-10, and tumor necrosis factor [TNF]-α) or elafin, and a dermatology consultation. Rashes were categorized as simple morbilliform rash without systemic involvement or complex morbilliform rash with systemic involvement. RESULTS: Fifty-four of 144 (37.5%) patients died during follow-up. Elevated levels of IL-6, IL-10, and TNF-α were associated with decreased survival. Overall survivals in patients with elevated levels of IL-6, IL-10, and TNF-α were 53.7%, 56.6%, 53.6%, respectively, compared with 85.7%, 82.5% and 83.6%, respectively, in those with lower levels. Patients with increased levels of both IL-6 and TNF-α had a nearly 6-fold increase in mortality (hazard ratio, 5.82) compared with patients with lower levels. LIMITATIONS: Retrospective design, limited sample size, and high-risk population. CONCLUSIONS: Hospitalized patients with cancer with rash and elevated IL-6 and TNF-α were nearly 6 times more likely to die over the course of follow-up. These biomarkers may serve as prognostic biomarkers and therapeutic targets for this high-risk population.

Severe cutaneous adverse reaction associated with antiseizure medications: Diagnosis, management, and prevention.

Severe cutaneous adverse reactions (SCARs) are potentially life-threatening, with considerable morbidity and mortality. They are nonimmediate hypersensitivity reactions that occur in specifically predisposed patients with delayed T-cell-mediated hypersensitivity reaction. Antiseizure medications (ASMs) are among the drugs that can induce SCAR. Increased awareness of SCAR among clinicians treating patients with ASMs is critically important for early recognition of symptoms, prompt identification and removal of the causal drug, and early intervention to reduce SCAR-related acute and long-term morbidity and mortality. The diagnosis, management, and prevention of Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS) are reviewed, along with the current understanding of the pathomechanisms and role of genetics in SCAR development. Supportive care and immunomodulating treatments for SCAR are discussed.

Antibacterial antibiotic-induced drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome: a literature review.

BACKGROUND: Drug reaction with eosinophilia and systemic symptoms syndrome (DRESS) is a delayed infrequent potentially life-threatening idiosyncratic drug reaction. Aromatic anticonvulsants and allopurinol are the most frequent causative agents. However, various reports of antibiotic-induced DRESS are available. In this review, we try to summarize reports of antibacterial antibiotic-induced DRESS focusing on characteristics of DRESS induced by each antibiotic group. METHODS: The data were collected by searching PubMed/MEDLINE and ScienceDirect. The keywords used as search terms were "DRESS syndrome," "drug-induced hypersensitivity syndrome (DIHS)," "antibiotics," "antimicrobial," and names of various antimicrobial groups. Finally, 254 relevant cases with a definite or probable diagnosis of DRESS based on RegiSCAR criteria were found until 30 May 2020 and reviewed. RESULTS AND CONCLUSION: Totally, 254 cases of antibacterial antibiotic-induced DRESS are reported. Most of them are related to antituberculosis drugs, vancomycin, and sulfonamides, respectively. Rash and fever were most frequent clinical findings. Eosinophilia and liver injury were the most reported hematologic and visceral organ involvement, respectively. Most of the patients are managed with systemic corticosteroids. The death occurred in 16 patients which most of them experienced liver or lung involvement. The reactivation of various viruses especially HHV-6 is reported in 33 cases. The mean latency period was 29 days. It is necessary to perform thorough epidemiological, genetic, and immunological studies, also systematic case review and causality assessment, as well as well-designed clinical trials for better management of antibiotic-induced DRESS.

Drug-induced hypersensitivity syndrome caused by minodronic acid hydrate.

BACKGROUND: Drug-induced hypersensitivity syndrome (DIHS)/drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is an important adverse reaction caused by a few drugs. Reactivation of human herpesvirus 6 (HHV-6) is known to be associated with its pathogenesis. DIHS occasionally manifests as pulmonary lesions with a variety of imaging findings. CASE PRESENTATION: An 83-year-old woman started taking minodronic acid hydrate 5 years before admission. She noticed a generalized skin rash 44 days before admission and started oral betamethasone-d-chlorpheniramine maleate combination tablets for allergic dermatitis. She developed a fever and cough in addition to the rash, and was referred to our hospital. Laboratory data showed a high level of eosinophils and liver and biliary enzymes. Computed tomography (CT) studies revealed bilateral diffuse ground-glass opacities with ill-defined centrilobular nodules from the central to peripheral regions of the lungs. Transbronchial lung cryobiopsy specimens showed that lymphocyte infiltration was observed in the alveolar walls and fibrinous exudates and floating macrophages in the alveolar lumina. Immunohistochemistry of biopsy specimens showed more CD4+ lymphocytes than CD8+ lymphocytes, while few Foxp3+ lymphocytes were recognized. The serum anti-HHV-6 immunoglobulin G titer increased at 3 weeks after the first test. Based on these findings, we diagnosed her with DIHS. We continued care without using corticosteroids since there was no worsening of breathing or skin condition. Eventually, her clinical symptoms chest CT had improved. Minodronic acid hydrate was identified as the culprit drug based on the positive results of the patch test and drug-induced lymphocyte stimulation test. CONCLUSIONS: We described the first case of DIHS caused by minodronic acid hydrate. Lung lesions in DIHS can present with bilateral diffuse ground-glass opacities and ill-defined centrilobular nodules on a CT scan during the recovery phase. Clinicians should be aware of DIHS, even if patients are not involved with typical DIHS/DRESS-causing drugs.

Role of Multiple Comorbidities and Therapies in Conditioning the Clinical Severity of DRESS: A Mono-Center Retrospective Study of 25 Cases.

DRESS/DiHS is a complex and potentially fatal drug reaction. Little is known about risk factors and elements that can help to identify patients with a severe reaction early. The aim of the study was to investigate those factors favoring the disease and its severity by analyzing the clinical conditions and therapies preceding the reaction. We conducted a retrospective analysis on patients admitted to our center between 2010 and 2020 who were discharged with a diagnosis of DRESS. We used the RegiSCAR diagnostic criteria. We defined the severity of DRESS using the criteria of Mizukawa et al. We included 25 patients (15 females) with a median age of 66 years. Skin involvement, eosinophilia, and liver injury were the most important aspects. Allopurinol was found to be the most involved drug. Reaction severity was significantly associated with the number of daily medications (p=0.0067) and an age of at least 68 years (p=0.013). In addition, 75% of severe cases had at least three comorbidities in history, and most of the severe cases were female. In our study the advanced age, the high number of comorbidities and home therapies, and the inflammatory state were found to be predisposing elements to the development of the disease and its severity.

Current Perspective Regarding the Immunopathogenesis of Drug-Induced Hypersensitivity Syndrome/Drug Reaction with Eosinophilia and Systemic Symptoms (DIHS/DRESS).

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) is a severe type of adverse drug eruption associated with multiorgan involvement and the reactivation of human herpesvirus 6, which arises after prolonged exposure to certain drugs. Typically, two waves of disease activity occur during the course of DIHS/DRESS; however, some patients experience multiple waves of exacerbation and remission of the disease. Severe complications, some of which are related to cytomegalovirus reactivation, can be fatal. DIHS/DRESS is distinct from other drug reactions, as it involves herpes virus reactivation and can lead to the subsequent development of autoimmune diseases. The association between herpesviruses and DIHS/DRESS is now well established, and DIHS/DRESS is considered to arise as a result of complex interactions between several herpesviruses and comprehensive immune responses, including drug-specific immune responses and antiviral immune responses, each of which may be mediated by distinct types of immune cells. It appears that both CD4 and CD8 T cells are involved in the pathogenesis of DIHS/DRESS but play distinct roles. CD4 T cells mainly initiate drug allergies in response to drug antigens, and then herpesvirus-specific CD8 T cells that target virus-infected cells emerge, resulting in tissue damage. Regulatory T-cell dynamics are also suggested to contribute to the diverse symptoms of DIHS/DRESS. However, the pathomechanisms of this complex disease remain largely unknown. In particular, how viral infections contribute to the pathogenesis of DIHS/DRESS and why autoimmune sequelae arise in DIHS/DRESS are yet to be elucidated. This review describes the clinical features of DIHS/DRESS, including the associated complications and sequelae, and discusses recent advances in our understanding of the immunopathogenic mechanisms of DIHS/DRESS.

Drug Reaction with Eosinophilia and Systemic Symptoms: A Complex Interplay between Drug, T Cells, and Herpesviridae.

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, also known as drug induced hypersensitivity (DiHS) syndrome is a severe delayed hypersensitivity reaction with potentially fatal consequences. Whilst recognised as T cell-mediated, our understanding of the immunopathogenesis of this syndrome remains incomplete. Here, we discuss models of DRESS, including the role of human leukocyte antigen (HLA) and how observations derived from new molecular techniques adopted in key studies have informed our mechanism-based understanding of the central role of Herpesviridae reactivation and heterologous immunity in these disorders.

DiHS/DRESS syndrome induced by second-line treatment for tuberculosis and Epstein-Barr virus.

Drug-induced hypersensitivity syndrome (DiHS) or drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a severe adverse drug-induced reaction characterized by various symptoms: skin rash, fever, lymph node enlargement and internal organ involvement, which starts within 2 weeks to 3 months after drug initiation. It is challenging to diagnose this syndrome due to the variety of cutaneous and visceral symptoms. Different mechanisms have been implicated in its development, including genetic susceptibility associated with human leucocyte antigen (HLA) loci, detoxification defects leading to reactive metabolite formation and subsequent immunological reactions, slow acetylation, and reactivation of human herpes, including Epstein-Barr virus and human herpes virus (HHV)-6 and HHV-7. The most frequently reported causes of DiHS/DRESS are antiepileptic agents, allopurinol and sulfonamides. We report a case of DiHS/DRESS induced by second-line treatment for tuberculosis, prothionamide and para-aminosalicylic acid, and Epstein-Barr virus re-infection. Patch testing, which was performed in this case, is not fully standardized, but it can be helpful and a safe way to evaluate and diagnose DiHS/DRESS.