Acute Generalized Exanthematous Pustulosis Induced By Topical Morphine And Confirmed By Patch Testing

To the Editor: Acute generalized exanthematous pustulosis (AGEP) is a rare adverse cutaneous reaction to several triggers, where oral medications constitute themajority of the identified triggers. Acute generalized exanthematous pustulosis is clinically characterized by the acute appearance of generalized edematous erythema, speckled with small pinheaded nonfollicular sterile pustules that can become confluent, usually with accompanying fever (≥38.5°C) and peripheral blood leukocytosis, with marked neutrophilia. We report here a case of AGEP after topical application of a combination of lidocaine with 10% morphine, confirmed by patch testing. A 72-year-old woman presented to her general practitioner with back pain and was prescribed lidocaine with 10% morphine formulation to be applied topically. Within 10 days after initiation of topical application, she developed severe generalized pustular erythema with a fever of 39°C (Fig. 1A). Histological examination of a lesional biopsy showed epidermal spongiosis, subcorneal/superficial epidermal pustules, and inflammation around adnexal structures (Figs. 1B, C). The clinical and histological findings were consistent with AGEP. The symptoms resolved after discontinuation of the topical application and initiation of a short course of oral prednisone. We elected to patch test the patient to the following: the North American Contact Dermatitis Group standard screening