Patch Testing for Drugs:

A case of bortezomib (Velcade)-induced Stevens-Johnson syndrome confirmed by patch test

Bortezomib, a highly selective reversible inhibitor of the proteasome complex, is used to the current standard of care in the treatment of multiple myeloma. Although its most commonly reported side effects are gastrointestinal symptoms, peripheral neuropathy, neuropathic pain, and thrombocytopenia, cutaneous adverse reactions are also frequently seen. However, severe cutaneous adverse reactions (SCAR) such as Stevens-Johnson syndrome (SJS) occur very rarely. Here we report the first case of bortezomib-induced SJS with confirmed by patch test. In this case, we performed a patch test that proved bortezomib was the offensive drug in this patient, who had been treated with multiple drugs including antibiotics, allopurinol, and anticancer drugs. Although bortezomib-induced SCARs are generally very rare, we suggest that clinicians be aware of potential adverse reactions including SJS.

Probable etoricoxib-induced fixed drug eruption involving the oral mucosa: A case report

Fixed drug eruption (FDE) is a cutaneous adverse drug reaction characterized by recurrence of lesions at the same sites each time a specific drug is taken. Oral mucosal involvement is rare. Nonsteroidal anti-inflammatory drugs are one of the most common offending drug groups in FDE; however, selective cyclooxygenase-2 inhibitors, such as etoricoxib, are rarely implicated. We present a case of oral mucosal and cutaneous FDE induced by etoricoxib that, to the best of our knowledge, is the first reported case of this nature. We describe the diagnostic challenges and review the pertinent literature. The value of drug provocation testing and patch testing in FDE is also discussed.

Cutaneous Adverse Drug Reactions in Dogs Treated with Antiepileptic Drugs

Epilepsy is one of the most common neurologic disorders in dogs and life-long treatment with antiepileptic drugs (AED) is frequently required. Adverse events of AED targeting the skin are only rarely reported in veterinary medicine and the true incidence and spectrum of cutaneous reactions in epileptic dogs remains unknown. In this study, we hypothesized that cutaneous reactions commonly occur in epileptic dogs and are related to AED treatment. A retrospective case review of 185 dogs treated for epilepsy identified 20.0% with simultaneous appearance of dermatologic signs. In a subsequent prospective case investigation (n = 137), we identified newly appearing or distinct worsening of skin lesions following initiation of AED therapy in 10.9% of dogs treated for epilepsy (95% CI 6.8–17.7%). Cutaneous lesions were classified as probably drug-induced in 40.0% of these cases. Patch testing and intradermal testing were further investigated as potential diagnostic methods to confirm AED hypersensitivity. They were of high specificity but sensitivity and positive predictive value appeared inappropriate to recommend their routine use in clinical practice.

[Delayed-type cutaneous drug reactions. Pathogenesis, clinical features and histology]

BACKGROUND

Cutaneous reactions to drugs can be subdivided in different ways. In addition to the standard classification according to the etiopathogenesis there are also classifications based predominantly on morphological criteria. The majority of drug-related cutaneous adverse reactions are immunological reactions which are collectively classified under the term hypersensitivity. These reactions are based on drug-specific immunoglobulin E (IgE) or cell-mediated mechanisms, not on the mechanism of action of the drug and are unpredictable. Delayed type reactions to drugs are forms of type IV T-cell mediated hypersensitivity. A prerequisite is a stable association of a pharmaceutical substance with a protein so that hapten-protein conjugates can be produced. The most common clinical symptom is maculopapular (morbilliform) drug-related exanthema. This article also examines lichen planus like drug reaction and drug-induced (hematogenic) allergic contact dermatitis in more detail.

DIAGNOSTICS

The diagnostics are never trivial but also include the differentiation from viral exanthema and initial phases of severe cutaneous adverse reactions, such as toxic epidermal necrolysis. In addition to the morphological classification, the final diagnosis encompasses the interpretation of histopathological alterations in the skin biopsy, analysis of patient medication history, laboratory results and inclusion of data from the literature. Patch tests can also have additional diagnostic benefits. In vitro tests which involve the cellular incubation of the drug responsible should be reserved for specialized laboratories. A prerequisite for successful treatment is immediate termination of the drug responsible.

THERAPY AND PROGNOSIS

Therapy is symptomatic with topical and also short-term systemic steroids and antihistamines. The prognosis is very good.

Erythroderma secondary to gliclazide: a case report

Erythroderma is generalized exfoliative dermatitis, which involves more than 90% of the patient's skin. The most common cause of erythroderma is exacerbation of an underlying skin disease, malignancies or drug reaction. There is a long list of drugs responsible for erythroderma such as antiepileptics, sulfonamides, antibiotics, and angiotensin converting enzyme (ACE) inhibitors. We herein report a case of erythroderma due to gliclazide usage which is also proved by histopathologic examination and patch test. We could not find any case report of gliclazide, an oral antidiabetic, as a cause erythroderma in the literature.