Norwegian scab (or crust ) is a particular clinical form of the parasitosis, so called because it was first described in 1848, in Norway.
Norwegian scabies is extremely contagious and affects mainly those who are immunosuppressed due to the outcome of diseases (eg neoplasms, AIDS and neuropathies) or treatments (eg transplants or therapy with corticosteroids or other immunosuppressive drugs). The host's diminished immune defenses favor the massive proliferation of Sarcoptes scabiei mites on the skin, making the Norwegian scabies very difficult to cure.
Norwegian scab is manifested by squamous-crusted lesions, especially on the palmar-plantar level, on the back of the hands and on the knees. Unlike the classical clinical form, itching is discreet or absent, so the diagnosis is delayed and thus increases the risk of infecting other people.
