Topical retinoids are important tools in the management of acne because they act against comedones and microcomedones and have direct anti-inflammatory effects. The substances approved for acne treatment comprise tretinoin (all-trans-retinoic acid), isotretinoin (13-cis retinoic acid) as well as the synthetic third-generation polyaromatic retinoids adapalene and tazarotene, the latter being approved for acne treatment in the US only. Retinaldehyde is used in cosmetic preparations against acne.
All topical retinoids are effective as single agents in mild to moderate acne but differ in efficacy and tolerability. Tazarotene 0.1 % is more effective than tretinoin 0.025 % or 0.1 % microsphere gel or adapalene 0.1 % gel or cream (EBM-level 2c). Adapalene 0.1 % is equally effective to tretinoin 0.025 % or tretinoin microsphere 0.1 % gel or tretinoin 0.05 % cream or isotretinoin 0.05 % gel (EBM-level 2c). Adapalene 0.1 % gel is significantly better tolerated than tazarotene 0.1 % gel, tretinoin 0.025 % and tretinoin 0.05 % gel, tretinoin 0.05 % cream, tretinoin microsphere 0.1 % gel or isotretinoin 0.05 % gel (EBM-level 2c). The safety profile of topical retinoids differs from their systemic counterparts and is related mainly to local adverse effects, such as erythema, dry-ness, itching and stinging. The currently available evidence justifies the use of topical retinoids in most types of acne and during maintenance treatment.