What is Norwegian scabies?

Norwegian (crusted) scabies is a massive infestation with inordinate numbers of scabies mites due to inadequate host response. The large numbers of organisms cause a hyperplastic growth of the epithelium. Scratching may be absent because itching is variable. The condition is seen in debilitated patients, those with mental illness, sensory neuropathy, paresis, and immunosuppressed patients such as those with acquired immune deficiency syndrome, post-transplantation, or undergoing topical or systemic corticosteroid therapy. Topical treatment with permethrin and keratolytics is difficult, so oral ivermectin (200 µg/kg) has been used with good success.

Tran L, Siedenberg E, Corbett S: Crusted (Norwegian) scabies, J Emerg Med 22:285–287, 2002.