Vitamin A,
Vitamin A acid (
retinoic acid) and their synthetic derivatives were variously applied in the management of
psoriasis with different therapeutic results. Obviously, they influence the proliferation rate and the differentiation of human keratinizing epithelia and have beneficial effects on
skin diseases with disturbances of keratinization, including
psoriasis. Systemic application of
Vitamin A has been yet largely abandonned since high dosages leading to clearing develop evident systemic toxicity. The anti-psoriatic effect of
Vitamin A acid is either moderate or restricted, because of side effects. Only its combined local application with topical
corticosteroids may be considered. Oral application of newly synthesized
retinoids, however, was beneficial in
psoriasis, particularly in erythrodermic or pustular types. With this group of
retinoids new pathways were opened in dermatotherapy which may help to replace
cytostatic drugs in these cases. Additionally, oral
retinoid treatment may be introduced as an adjuvans in the management of widespread
psoriasis, in order to enhance the effect of
anthralin, PUVA or UVB treatments.