Erythema multiforme caused by sildenafil in an HIV(+) subject.

Erythema multiforme is mainly caused by drug allergy and infections. This is the case of a HIV-positive, 49-year-old male, recently cured for syphilis, that presented erythema multiforme minor, five days after taking sildenafil. He had a fast recovery, only with the use of antihistamines. Cell-mediated allergy to sildenafil was confirmed six months later, with the use of patch-tests.