This is because detecting the underlying cause of erythroderma may be difficult. In addition to a careful skin examination, obtaining information about a history of a pre-existing dermatosis may be helpful. Multiple skin biopsies are often necessary. The histology varies according to the underlying disease, but often the biopsy findings are non-specific with features of a spongiotic dermatitis. In chronic erythroderma, serial biopsies may eventually reveal cutaneous T-cell lymphoma.
Laboratory studies can reveal low albumin, elevated gamma globulin and an electrolyte imbalance.
When clinically indicated, bacterial cultures of the skin and blood should be taken. If the erythroderma temporarily clears patch tests could be useful. A bone marrow examination should be done if leukemia is suspected. Initial management requires hospitalization to monitor the patient closely. There is significant heat loss because of capillary dilatation in the skin.