Acne vulgaris is a chronic dermatological disorder that affects the majority of teenagers in the Western world. Topical therapy is widely used to treat mild-moderate acne and is known as well-tolerated thanks to its low systemic toxicity, although associated to skin adverse effects. Acne seems to be associated also to an intrinsic alteration of the epidermal barrier, regarding both the upper and the follicular stratum corneum that promotes the onset of such local side effects. The commonest one is irritant contact dermatitis, an event of frequent observation occurring with erythema, burning, dryness, scaling, and itching, usually characterized by low severity and limited duration. Among topical acne drugs, retinoids are the most irritating ones. Another side effect is allergic contact dermatitis: it is rare and mainly associated to benzoyl peroxide.