Cutaneous manifestations in rats with advanced vitamin A deficiency.

Specific-pathogen-free rats kept on a vitamin A-deficient diet for approximately 5 months developed cutaneous alterations, especially in the periorbital and eyelid skin. These lesions were characterized grossly by erythema, partial alopecia, and crusting, and histologically by hyperorthokeratinization, acanthosis, and a three-fold increase in incorporation of labeled DNA precursors into the epidermal basal layer. Electron microscopy showed an increased number of Langerhans cells with and without Birbeck granules, as well as the presence of cytoplasmic dense bodies of probable lipid nature in keratinocytes of all epidermal strata. The similarities of these ultrastructural alterations with some features of vitamin A-sensitive human dermatoses point to probable common mechanisms in the pathogenesis of these skin diseases.