Results of patch testing in acute generalized exanthematous pustulosis (AGEP): A literature review

The literature on positive patch-test results in acute generalized exanthematous pustulosis (AGEP) is reviewed. Ninety-three drugs were identified that have together caused 259 positive patch tests in 248 patients with AGEP. The drug classes causing the highest number of reactions are beta-lactam antibiotics (25.9%), other antibiotics (20.8%), iodinated contrast media (7.3%), and corticosteroids (5.4%), together accounting for nearly 60% of all reactions. The highest number of reactions to individual drugs was to amoxicillin (n = 36), followed by pristinamycin (n = 25), diltiazem (n = 14), amoxicillin-clavulanic acid (n = 13), clindamycin (n = 11), and iomeprol (n = 8); 59 of the 93 drugs each caused a single case only. The "Top-10" drugs together caused over 50% of all reactions. The sensitivity of patch testing (percentage of positive reactions) in patients with AGEP is largely unknown, but may generally be ~50%, which also applies to pristinamycin. Patch testing in AGEP appears to be safe, although mild recurrence of AGEP skin symptoms or other rashes may occur occasionally. Clinical aspects of AGEP, including epidemiology, etiology and pathophysiology, clinical features, histology, treatment, and prognosis are briefly presented, as are diagnosing the disease and identifying the culprit drugs with patch tests, intradermal tests, in vitro tests, and challenge tests.