Oral
retinoids, synthetic derivatives of
vitamin A, have been used in the treatment of various
dermatoses over the last decade. The most useful drugs have been
isotretinoin (13-cis-retinoic acid) for nodulocystic
acne and
etretinate for
psoriasis vulgaris.
Retinoids are also effective in the treatment of papulosquamous
dermatoses other than
psoriasis (i.e. inherited disorders of keratinisation),
cutaneous T-cell lymphoma and in
chemotherapy and
chemoprevention of
cancer. However, systemic administration of these compounds is frequently associated with mucocutaneous side effects, liver toxicity and abnormalities of serum
lipid profiles, which might be related to an increased risk of
coronary heart disease. Of particular concern is the teratogenic effect of all
retinoids, which limits their use in women of child-bearing potential. Chronic toxicities from long term
therapy with
retinoids may result in skeletal abnormalities, usually mimicking diffuse idiopathic
hyperostosis syndrome. Furthermore, the chronic use of
retinoids in children may inhibit their growth due to premature epiphyseal closure. In contrast to other side effects of
retinoids which are dose dependent and reversible upon withdrawal of the
drug, it seems unlikely that bone abnormalities will resolve after discontinuation of the medication. In view of the wide spectrum of toxicities, treatment with
retinoids requires appropriate selection of patients, careful consideration of the benefit to risk ratio for each individual, periodic monitoring of clinical response and laboratory tests. Clinicians should use special management techniques in order to prevent or minimize slide effects. Extensive investigations are currently being conducted in an attempt to develop new
retinoids which will improve the therapeutic efficacy and reduce unwanted reactions.