(BMJ)—A 62-yo man w/ hx of recurrent oral ulcers, sometimes w/ laryngitis, and conjunctivitis presented w/ acute-onset fever, odynophagia, and laryngitis x2 days. He was prescribed ibuprofen and clarithromycin. Two days later, conjunctivitis, oral erosions, and target lesions on his trunk, lower limbs, and scrotum appeared, and he was hospitalized on suspicion of having Stevens-Johnson syndrome. However, this was not the dx. What was the dx?
Toxic epidermal necrolysis
Paraneoplastic pemphigus
Erythema multiforme
Behçet dz
Drug reaction w/ eosinophilia and systemic sx
You are correct. A dx of erythema multiforme major was made based on the typical target lesions w/ 3 concentric rings, and widespread oral, ocular, and genital mucous membrane erosions, which are suggestive of the “major” subtype. Erythema multiforme is frequently confused w/ Stevens-Johnson syndrome and toxic epidermal necrolysis because of the similarities in the appearance of mucous membrane lesions. Previous episodes of oral ulcers, sometimes w/ laryngitis and conjunctivitis, are indicative of erythema multiforme. Some 40% of pts w/ erythema multiforme experience multiple recurrences, esp when the condition is triggered by herpes simplex virus. This pt was treated w/ enteral nutrition, topical steroids, and steroid mouthwashes. He improved, w/ healing of all cutaneous and mucosal lesions, and was discharged after 8 days.

BMJ 2017;359:j3817