A 44-year-old otherwise healthy man presented with pruritic linear erythematous plaques on his left wrist. Two weeks prior, the patient had been doing some garden work in his backyard while wearing shorts and a T-shirt. By the following morning, he developed a pruritic vesiculobullous erythematous eruption on the left wrist in streak-like arrangements.
The patient applied an over-the-counter 1% hydrocortisone cream and polysporin ointment several times a day on the affected area but without much improvement of the rash or pruritus. There was no history of insect bites or contact with animals. The patient suspected that the eruption was related to a plant that he accidentally cut in the backyard. The plant had 3 leaflets per stem.
Poison ivy dermatitis is the most common allergic contact dermatitis in the United States. The condition was first described by Nicholson in 1899 who reported a young woman with contact dermatitis after pruning a creeper. Her father ordered a servant to cut the plant down and the servant developed a widespread allergic contact dermatitis. The plant was subsequently identified to be poison ivy.
Poison ivy belongs to the genus Toxicodendron (previously classified as in the genus Rhus) and the family Anacardiaceae. Eastern poison ivy (T radicans) is a small shrub or climbing vine that grows mainly east of the Rocky Mountains. Western poison ivy (T rydbergii) is a non-climbing shrub that grows mainly in the northern United States and in Southern Canada. The leaves of poison ivy are usually notched and in groups of three. The flowering branches arise from axillary positions on a single stem.
The patient was treated with ultra-potent topical steroids twice a day for 10 days and the rash and itch promptly resolved.