Topical drug treatment in acne.

The main part of acne treatment uses the topical route. More than 50% of acne patients belong to the group presenting with acne comedonica and papulopustulosa. Whenever small nodes or scarring occur, systemic comedication is indicated, however. Topical treatment affects at least three of the four main pathogenetic factors responsible for the development of acne, i.e. hyperseborrhea, hyperkeratosis, microbial colonization and inflammation. The agents currently available influence at least one of these factors but often have additional properties. Those which act in a comedolytic and anticomedogenic manner are the retinoids tretinoin, isotretinoin, adapalene and tazarotene and azelaic acid as well, some of the retinoids having additional anti-inflammatory potency. Azelaic acid has strong antibacterial potency without inducing bacterial resistance similar to benzoyl peroxide. Unfortunately, bacterial resistances are beginning to emerge as a significant problem. Propionibacterium acnes resistance to the commonly used erythromycin can also be transferred to clindamycin, whereas no resistance has been reported to nadifloxacin so far. Today, more and more evidence comes up that topical antiandrogenic agents will soon be available to treat the important factor seborrhea, because patients with marked hyperseborrhea frequently relapse. Finally, liposome encapsulation of agents including phospholipids can enhance penetration and efficacy but, particularly with regard to retinoids, can lead to higher absorption and adverse drug reactions.