This 18-year-old young man had been exposed to poison ivy 2 weeks previously and had developed Rhus allergic contact dermatitis on his legs that had responded to potent topical corticosteroids. He now presented with a few-day history of circular lesions on his hands, trunk, and extremities (with sparing of the mucous membranes) that he described as itchy and tender. He was otherwise healthy, and he denied any new medications and any recent upper respiratory infections or fever blisters.
ANSWER: Erythema multiforme induced by poison ivySee the full case at Consultant360
Rhus allergic contact dermatitis–induced erythema multiforme (EM) is an underreported but well-documented occurrence.1,2 Fortunately, this condition usually responds to treatment with systemic corticosteroids.
Urticaria tends to come and go, unlike these lesions, which have been present for a few days. There was no history of contact dermatitis, and the target-like lesions are characteristic of EM, not contact dermatitis. Measles starts with fever, runny nose, cough, red eyes, and sore throat, followed by a rash that spreads over the body with accompanying oral lesions, unlike what is seen in this patient’s case.References
David L. Kaplan, MD, is a clinical assistant professor of dermatology at the University of Missouri–Kansas City School of Medicine in Kansas City, Missouri, and at the University of Kansas School of Medicine in Kansas City, Kansas. He practices adult and pediatric dermatology in Overland Park, Kansas.