Images of Memorable Cases: Case 34 This AIDS patient presented with a pruritic eruption over most of his body. The lesions appeared as sharply demarcated, thick plaques with distinct borders and silvery scales. 34. Hyperkeratotic psoriasis Biopsies from several plaques established the diagnosis. In patients with AIDS, psoriasis is often severe and refractory to conventional therapy. The differential diagnosis includes Norwegian scabies, mycosis fungoides, and keratoderma blenorrhagica.