Norwegian Scabies

A 52-year-old white man presented with a pruritic eruption on the neck of 3 months' duration. The rash had not responded to a potent topical corticosteroid prescribed by another practitioner for the presumed diagnosis of eczema.

The patient reported no current health problems. His history included a pubic louse infestation and several episodes of uncomplicated urethral gonorrhea. He readily admitted to having unprotected sexual intercourse with prostitutes.

Ted Rosen, MD, of Houston writes that a heavily crusted, fissured plaque encircled the patient's neck and extended to the upper chest and ears. The differential diagnosis included chronic contact dermatitis; Hailey-Hailey disease; severe atopic eczema; and crusted, or Norwegian, scabies. Innumerable scabies mites were revealed by microscopic examination of a skin scraping placed in mineral oil; Norwegian scabies was diagnosed.

Norwegian scabies is a severe, although rare, form of scabies caused by the mite Sarcoptes scabiei. Crusting dermatitis of the hands and feet and erythematous scaling plaques on the neck, head, and back are characteristic. Lymphadenopathy and eosinophilia may also be present, as was the case in this patient.

The infestation was successfully treated with 3 oral doses of ivermectin, 200 µg/kg, administered 2 weeks apart and topical applications of permethrin cream. The patient's history of recurrent sexually transmitted disease and the Norwegian scabies infestation suggested immunosuppression and possible HIV disease. Serologic examination determined the patient was seropositive for HIV. He was lost to follow-up.