Dermatitis caused by aquatic worms

Abstract

Various aquatic worms induce injuries by traumatic or poisonous mechanisms, through bites or contact with the bristles on their bodies. Cercarial dermatitis, induced by non human-parasitizing schistosomes in bathers and underwater divers, can also be observed in subjects working with freshwater for irrigation purposes (agricultural workers and rice growers). Clinical manifestations are observed in allergic subjects. Leeches, that inhabit freshwaters, inject an anticoagulant and other antigenic substances with their bites: in allergic subjects there may be the onset of urticarial, blistering or necrotic and even anaphylactic reactions. The Polychaeta venom apparatus is present in the bristles and jaws, and can induce local skin reactions and anaphylactic reactions. Fishermen using lines can present with a peculiar contact dermatitis of the fingertips and nails of the hands, due to the coelomic liquid of a marine annelid worm used as bait. Larva migrans cutanea (“creeping eruption”), induced by the migration of nematode larvae through the skin, presents with linear erythemato-papular lesions, slightly raised above the surrounding skin. Oncocerciasis, caused by a nematode, affects the skin and eyes (“river blindness”). Skin manifestations can show a morphological evolution over time. Acute erythemato-papulous exanthematic pruriginous eruptions evolve to diffuse lichenification and, in a further phase, to hypotrophy or atrophy and hypo- and achromic lesions (a “leopard skin appearance”). Delayed skin complaints can manifest with onchocercomata, while involvement of the lymph nodes leads to elephantiasis of the genitalia.