retinoidien

Retinoids are a class of compounds derived from vitamin A or synthetic analogs that modulate gene expression by binding to nuclear retinoic acid receptors (RARs) and retinoid X receptors (RXRs). They include natural retinoids such as retinol, retinal, and retinoic acid, as well as synthetic analogs such as tretinoin (all-trans retinoic acid), adapalene, isotretinoin, and tazarotene.

Mechanism of action involves binding to RARs and RXRs, which alters transcription of genes involved in cell differentiation, proliferation, and apoptosis. In the skin this leads to normalization of keratinocyte maturation, increased epidermal turnover, reduced comedone formation, and anti-inflammatory effects. Systemically, retinoids influence differentiation and proliferation of various cell types and have applications in oncology.

Applications of retinoids span dermatology and oncology. Topical retinoids are used to treat acne and signs of photoaging, with improvements in fine lines, pigment in the skin, and texture. They are also used for psoriasis and certain keratinization disorders. Isotretinoin, an oral retinoid, is reserved for severe nodulocystic acne or refractory cases. In medicine, all-trans retinoic acid is employed in the treatment of acute promyelocytic leukemia, reflecting their influence on cell differentiation.

Safety and handling require attention to irritation, redness, and peeling, especially during initiation. Retinoids increase photosensitivity, so daily sunscreen is advised. They are generally teratogenic and require pregnancy prevention programs for systemic forms. Use with caution in combination with other irritants or peeling agents and adapt dosing gradually to minimize adverse effects.

Formulations vary by region and intensity. Topical retinoids are prescription in some areas and OTC at lower strengths in others; oral isotretinoin is tightly regulated.