Erythroderma. 2 main causes are "acquired erythroderma" (= "acquired ichthyosis") and "erythrodermic psoriasis". Both can be induce by a drug allergy (including antiviral treatment) but; in practice there is one importand difference: unlike "acquired erythroderma"; "erythrodermic psoriasis" will relapse over a life time, even if you stop the drug which induced the problem. See "30-erythroderma"