Beware the Manchineel: A Case of Irritant Contact Dermatitis

The manchineel tree (Hippomane mancinella) grows along the sand-vegetation boundary of Caribbean beaches. The tree also can be found in Florida and the US Virgin Islands. All parts of the tree are toxic. Contact with the sap can cause severe irritant dermatitis and keratoconjunctivitis; eating the fruit can be fatal. Indigenous people were well aware of these properties, and early European explorers of the Caribbean coastlines mentioned the dangers of the plant in their writings. However, the medical literature provides scant information on the clinical evaluation and histopathology of manchineel dermatitis. This case report describes a physician (S.A.N.) who developed manchineel dermatitis while traveling in the US Virgin Islands. The dermatitis manifested as folliculocentric pustules. The patient subsequently underwent a skin biopsy, and histopathology showed a subcorneal acantholytic blister and epidermal spongiosis overlying a mixed perivascular infiltrate and follicular necrosis. The area was treated with hot compresses. Complete resolution took 6 weeks. There is no uniformly recommended treatment for manchineel dermatitis; prevention depends on avoiding contact with the tree.