Evidence for anti-inflammatory activities of oral synthetic retinoids: experimental findings and clinical experience.

Oral retinoids obviously influence dermal components such as cutaneous capillaries and dermal inflammatory cells in addition to their well-known action on keratinizing epithelia. On this basis, they act as an anti-inflammatory drug. In particular, they reduce the elevated skin temperature, inhibit the motility of neutrophils and eosinophils and their migration into the epidermis, decrease DNA synthesis of human lymphocytes by blocking their response to lectins and stimulate Langerhans cells, monocytes and macrophages in various in vitro and in vivo models. These data indicate that oral retinoids may not only normalize disorders of keratinization but also exert distinct therapeutic effects on various skin diseases with dermal inflammatory involvement regardless of their particular aetiology. In some respects, retinoids resemble corticosteroids, acting as a modified hormone. Preliminary clinical experiences with oral retinoid treatment in skin diseases such as cutaneous disseminated LE, bullous pemphigoid, Duhring's disease, pemphigus, Behçet's disease and necrotizing vasculitis with eosinophilia support these data. Monotherapy or combined administration of oral retinoids with corticosteroids in low doses seems therapeutically beneficial in these disorders.