ICD-10 Specific code L70: Acne

Adapalene is a retinoid-like compound which in, in vivo and in vitro models of inflammation, has been demonstrated to possess anti-inflammatory properties. Mechanically, adapalene binds like tretinoin to specific retinoic acid nuclear receptors but, unlike tretinoin not to cytosolic receptor binding proteins. Adapalene is used in the treatment of acne and is also used (off-label) to treat keratosis pilaris as well as other skin conditions.

Azelaic Acid is a naturally occurring dicarboxylic acid. Azelaic acid possesses antibacterial, keratolytic, comedolytic, and anti-oxidant activity. Azelaic acid is bactericidal against Proprionibacterium acnes and Staphylococcus epidermidis due to its inhibitory effect on the synthesis of microbial cellular proteins.

Benzoyl peroxide is a highly lipophilic, oxidising agent with keratolytic and bacteriocidal effects. The effectiveness of benzoyl peroxide in the treatment of acne vulgaris is primarily attributable to its antibacterial activity, especially with respect to Propionibacterium acnes. Benzoyl peroxide is also believed to be effective in the treatment of acne on account of its anti-inflammatory and mild keratolytic properties.

Tetracyclines have a broad spectrum of anti-microbial activity and act by interfering with bacterial protein synthesis. They are active against a large number of gram positive and gram negative pathogenic bacteria, including some which are resistant to penicillin.

Doxycycline is primarily bacteriostatic and is believed to exert its antimicrobial effect by the inhibition of protein synthesis.

Erythromycin exerts its antimicrobial action by binding to the 50S ribosomal sub-unit of susceptible microorganisms and suppresses protein synthesis. Erythromycin is bacteriostatic and bactericidal depending on its concentration and the type of organism.

Isotretinoin is a stereoisomer of all-trans retinoic acid (tretinoin). The exact mechanism of action of isotretinoin has not yet been elucidated in detail, but it has been established that the improvement observed in the clinical picture of severe acne is associated with suppression of sebaceous gland activity and a histologically demonstrated reduction in the size of the sebaceous glands. Furthermore, a dermal anti-inflammatory effect of isotretinoin has been established.

Tetracyclines are taken up into sensitive bacterial cells by an active transport process. Once within the cell they bind reversibly to the 30S subunit of the ribosome, preventing the binding of aminoacyl transfer RNA and inhibiting protein synthesis and hence cell growth.

Tretinoin decreases cohesiveness of follicular epithelial cells resulting in decreased microcomedone formation. Additionally, tretinoin stimulates mitotic activity and increased turnover of follicular epithelial cells, causing extrusion of the comedones.