Erythema multiforme after use of topical sulfacetamide

An 8-year-old boy developed erythema multiforme major after topical administration of sodium sulfacetamide for conjunctivitis. He had received systemic treatment with trimethoprim-sulfamethoxazole four months previously without evidence of drug allergy. There was no history of recent exposure to other drugs or evidence of herpes simplex or Mycoplasma infection. After 12 days of treatment with erythromycin ointment, 1% prednisolone eyedrops, systemic prednisone, and intravenous nafcillin, the patient's condition improved dramatically. A slit-lamp examination showed only superficial punctate keratitis. Two months later his visual acuity had improved from 20/200 bilaterally to R.E.: 20/40 and L.E.: 20/30.