Drug-Induced Pemphigus Workup

Updated: Jun 28, 2017
  • Author: Chris G Adigun, MD, FAAD; Chief Editor: Dirk M Elston, MD  more...
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Workup

Approach Considerations

Interferon-gamma release test

The interferon-gamma release test has been used in the diagnosis of drug-induced pemphigus. Initially, the patient is either exposed or not exposed to the drug; following exposure, the release of interferon-gamma from the patient’s lymphocytes is assessed with the use of an enzyme-linked immunosorbent assay (ELISA). The interferon-gamma release test allows for the identification of the specific drug that may be inducing pemphigus in the patient. The culprit drug is identified and can then be discontinued. [18]

Indirect immunofluorescence

Circulating autoantibodies are present in approximately 70% of patients with drug-induced pemphigus. When positive, indirect immunofluorescence findings usually reveal low titers of antibodies, which do not correlate with the severity of the disease. These antibodies recognize the pemphigus foliaceus antigen (desmoglein 1), pemphigus vulgaris antigen (desmoglein 3), or both. In drug-induced pemphigus, the presence of antibodies to desmoglein are diagnostic and allow prediction of outcome. [1] Circulating autoantibodies have been demonstrated to be more likely to occur in patients with non–thiol-induced pemphigus. In this group, the immunologic pattern and clinical course are similar to that of idiopathic pemphigus vulgaris. [19]

Direct immunofluorescence

Tissue-bound intercellular immunoglobulin G antibodies are diagnostic of pemphigus and are found in most patients (75-90%) with drug-induced pemphigus. A normal staining pattern of antidesmoglein 32-2B is an indicator for a good prognosis in drug-induced pemphigus. This can be used as a diagnostic tool in which studies have shown to have a 70.3% sensitivity and 83.9% specificity in confirming a diagnosis of drug-induced pemphigus. [20]

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Histologic Findings

Histologic features of established lesions correlate with the clinical appearance. Lesions resembling pemphigus foliaceus reveal superficial epidermal acantholysis, while those resembling pemphigus vulgaris reveal suprabasal acantholysis. Eosinophilic spongiosis may be present. It is not possible to distinguish between idiopathic and drug-induced pemphigus based on histologic features. [21]

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