Allergic contact dermatitis to mango flesh

A 22-year-old white female student presented to the Emergency Department with a 2-day history of patchy pruritic erythema of the face, neck, and arms with periorbital edema. The eruption began as an isolated patch of nasal erythema, with subsequent extension to involve the entire face. Within 2 days, fine pinpoint papules were noted on the face, anterior chest, neck, and upper extremities. Periorbital edema was present without intraoral abnormalities or laryngeal changes. An erythematous, mildly lichenified plaque was noted on the ventral left wrist. The past medical history was significant for two similar, milder episodes of allergic reactions of uncertain etiology occurring within the previous 2 months. The previous eruptions resolved after treatment with oral loratodine and topical fluocinonide cream 0.05%. The patient denied any history of contact urticaria or new household or personal hygiene contactants, although she did report frequent ingestion of peeled mangoes. Her brother had a history of eczematous dermatitis. In the Emergency Department, the patient was administered intravenous diphenhydramine and a single 50 mg dose of oral prednisone. She continued treatment with a 5-day course of prednisone, 50 mg daily, with loratodine, 20 mg daily, and diphenhydramine as needed; however, no symptomatic improvement was seen over 4 days. She was then advised to restart fluocinonide cream twice daily. Patch testing was performed to the North American Contact Dermatitis Group Standard Series utilizing methods of the International Contact Dermatitis research group with Finn chambers. Mango skin and mango flesh harvested 5 mm below the skin surface were also placed in duplicate and tested under Finn chambers. Positive (1+) reactions were noted to nickel and p-tertbutylphenol formaldehyde resin, and bullous reactions were found to mango skin and surface flesh in duplicate (Fig. 1). Complete avoidance of mango led to resolution of the initial eruption. The clinical relevance of nickel and p-tertbutylphenol formaldehyde resin was thought to be associated with the wrist lesion immediately below a glued portion of a wristwatch strap and metal clasp. Figure 1. Positive patch test reactions, in duplicate, to mango skin (left column) and mango flesh 5 mm below the skin (right column)