Cutaneous reaction to captopril: value of patch tests

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. 105 drugs were identified that have together caused 536 positive patch tests in 437 patients suffering from DRESS. By far 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 are 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 (far) 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. This article is protected by copyright. All rights reserved.

Captopril-induced lichenoid eruption

The case of a patient who developed remarkably extensive tumid nodules and plaques in a cobblestone pattern on the extensor aspects of the limbs is reported as a late presentation of captopril-induced lichenoid eruption. The severity and chronicity of our patient's symptoms and signs reflected delay in reaching the diagnosis.

Delayed hypersensitivity drug reactions diagnosed by patch testing

Drug reactions are a common problem in hospital inpatients and outpatients. Oral or parenteral drug challenges are valuable diagnostic aids, but time consuming. We review attempts to diagnose delayed hypersensitivity drug eruptions by patch testing. We review control data, and offer an operational definition that might make for greater acceptance of the rôle of diagnostic patch testing in this entity.