[Cercarial dermatitis or swimmer's itch--a little-known but frequently occurring disease in Norway].

Cercarial dermatitis or "swimmers' itch" has occurred in several places in Norway during the warm summer months. It is a maculopapular eruption associated with the penetration of the skin by cercaria of non-human schistosomes. Man is an accidental host, the primary hosts being birds or rodents. The penetration of the cercariae into the skin produces a prickling or itching sensation, followed by macules and papules or even urticarial and vesicular eruption in the case of heavy and repeated exposures. This allergic reaction is poorly understood. Two cases from the Oslo area are described. The treatment is entirely symptomatic. Antihistamines and cortisone cream may help to alleviate the itch.