Retinoids possess anti-proliferative, anti-inflammatory, immunoregulatory and pro-collagenogenic effects, and have been applied to the treatment of skin diseases. In recent years, clinical studies on topical retinoids have been mainly focused on comparisons among different classes and concentrations of retinoids, as well as therapeutic and adverse effects of them in combination with other drugs. Some progress has been made in their application to the treatment of keloid, acne vulgaris, photoaging, hyperpigmentation disorders, and regenerative effects, but their anti-tumor effects are still unclear. Unlike oral retinoids, there is no evidence that topical retinoids can cause fetal malformation. However, topical retinoids are not recommended for pregnant women yet. Adverse reactions to topical retinoids mainly manifest as local irritation, and systemic adverse reactions such as xerocheilia are also observed. The development of new drug delivery systems has optimized physicochemical properties of topical retinoids, and will further reduce adverse reactions and improve their therapeutic effects.

Skin diseases; Tretinoin; Administration, topical; Therapeutic uses