In patients with HIV infection, both the classic form and crusted Norwegian scabies (named because of its initial description in Norwegian patients with leprosy) can occur. The classic form can occur at any CD4 cell count, while Norwegian scabies is usually seen in patients with a CD4 cell count below 150 cells/μL.([112] Classic scabies presents as papulovesicular lesions. The distribution varies, favouring the wrists, interdigital web spaces, elbows, axillae, breasts and genitals. Predominantly night-time pruritus is usually seen. Due to the associated pruritus, excoriation of the lesions often occurs. Bacterial superinfection may occur with impetigo, cellulitis and, in some cases, fatal sepsis. In patients with neurological disorders or immunosuppression, the number of mites can increase unchecked due to the impaired immunity, absence of pruritus or the patient’s physical inability to scratch. Clinically, the eruption is suspected when there is marked thickening, often psoriasiform plaques, papules and crusting of the skin. It occurs primarily on the hands, although the entire body including the face and scalp is often involved.[113]