Tretinoin

Tretinoin, or all-trans-retinoic acid, is a topical retinoid used in dermatology. It activates retinoic acid receptors in skin cells, altering gene transcription and promoting turnover of keratinocytes. These actions help prevent comedone formation and improve epidermal texture.

Indications include acne vulgaris in adults and adolescents and mitigation of photodamage signs such as fine wrinkles and rough skin. It may also be used for certain keratinization disorders under specialist care.

Topical tretinoin is formulated as creams, gels, and solutions. Common concentrations are 0.01%, 0.025%, 0.05%, and 0.1%, with higher strengths used for more extensive or resistant disease.

Administration involves starting with low frequency and titrating as tolerated. Apply a pea-sized amount to cleansed, dry skin, avoiding eyes, lips, and mucous membranes. Sunscreen should be used daily.

Common adverse effects include local irritation (redness, dryness, peeling, burning) and temporary worsening of acne. Photosensitivity increases; rare systemic effects occur with extensive use. Tretinoin is teratogenic and contraindicated in pregnancy.

Interactions and cautions: avoid concurrent use with benzoyl peroxide, which can degrade tretinoin and irritate skin; if used together, apply at different times. Use with caution in older patients or those with eczema.

History and regulation: tretinoin was approved for dermatologic use in the 1960s–70s and remains prescription-only in many countries; brand names include Retin-A alongside generic formulations.