Hypereosinophilia in erythrodermic psoriasis: superimposed scabies.

Scabies is a common ectoparasitic disease that can be diagnosed based on the presence of pruritus and typical clinical signs including burrows, vesicles, and erythematous papules. If a desquamative disease such as psoriasis precedes scabies, then the disease course may be altered. Pruritus may be absent and typical scabies lesions may be concealed due to the preexisting disease, resulting in delayed diagnosis. We present 2 cases of scabies in a brother and sister with erythrodermic psoriasis. In both cases peripheral hypereosinophilia suggested scabies. In patients with erythematous scaly inflammatory skin diseases who are treated with immunosuppressive agents, peripheral eosinophilia also could suggest scabies; therefore, a search for sarcoptic mites in skin scrapings should be undertaken.