Acute exanthematous pustular drug eruption induced by mexiletine

A 56-year-old man developed infiltrated erythemas on the trunk, extremities, and face with marked facial edema, one month after taking mexiletine hydrochloride for his arrhythmia. A number of pustules were also noted on the surface of erythemas on his chest and face. Laboratory examination showed liver dysfunction and hypereosinophilia. The culture from pustules was sterile. Histological examination of the biopsied skin from a pustular lesion revealed a subcorneal abscess, and perivascular infiltration of lymphocytes, mononuclear cells and eosinophils in the upper dermis. The skin lesions and facial edema as well were improved within three weeks by withdrawal of mexiletine hydrochloride. Patch tests with 10% and 20% mexiletine hydrochloride in petrolatum showed positive reaction, however, pustules were not provoked on the tested site. We conclude that pustules, infiltrated erythema and facial edema were the signs of acute exanthematous pustular drug eruption induced by mexiletine hydrochloride.