Department of Human and Hereditary Pathology, University of Pavia, Italy.
Paederus fuscipes (PF) dermatitis is a self-healing blistering disorder of the skin caused by a small insect belonging to genus Paederus, family Staphylinidae, order Coleoptera. Crushing PF on the skin causes acute dermatitis within 24 hours, corresponding in shape and dimensions to the area affected by the substance released (pederin). The acute vesicular lesions become crusted and scaly within a few days and heal completely in 10-12 days, with a transitory postinflammatory hypercromic patch. Twenty consecutive cases of PF dermatitis at different stages were studied histologically by routine light microscopy. The pederin causes a spectrum of histopathologic changes ranging from acute epidermal necrosis and blistering in acute stages, to marked acanthosis with mitotic figures in the late stages. PF dermatitis is an entomological model of irritant contact dermatitis, having histopathologic features of intraepidermal and subepidermal blistering, epidermal necrosis and acantholysis. The presence of some acantholytic foci, relatively far from the foci of clinically involved skin, in four of the cases considered suggests a possible role of pederin in inducing acantholysis indirectly. Acantholysis is probably caused by the release of epidermal proteases.
Guilan Research Center for Skin Diseases, Rasht, Iran.
BACKGROUND: Paederus dermatitis develops when beetles of the genus Paederus (often called rove beetles) are crushed on the skin, releasing the vesicant pederin. These beetles are found in many tropical and subtropical habitats. METHODS: We describe 156 patients who presented to a dermatology clinic in the Guilan province of northern Iran during a 6-month period (May-October 2001). RESULTS: The peak time of presentation was in September, and the face and neck were the most common sites of involvement. Clinically, the most common presentation comprised geographic erythematous plaques with micropustules. In three-quarters of patients, more than one lesion was present. Kissing lesions were seen in 5% of cases, and 15% of patients developed diffuse desquamation. The majority of patients resided within 1 km of rice fields and used fluorescent lighting at home. In half of the cases, another family member was also affected. CONCLUSIONS: Paederus dermatitis is a common skin condition in northern Iran. We believe that increased public awareness of this condition can decrease mucocutaneous exposure to pederin.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1951984&dopt=Abstract
