ACNE VULGARIS

Pathophysiology--Multifactorial, including:

• Follicular hyperkeratinization (sheets of desquamated keratin plug the follicle)
• Sebum overproduction (stimulated by androgens)
• Bacterial infection (Propionibacterium acnes)
• Inflammatory reaction to same

Workup:

• Consider workup for androgen excess (free testosterone, LH and FSH) if signs are present, e.g. precocious puberty in males or females; or in females, menstrual abnormalities or virilization (hirsutism, clitoromegaly, male pattern baldness and deepening voice)

Treatments:

• Blue light in the 405-420nm wavelength range (15min 2x/wk x 4wks) has been shown to reduce # of acne lesions in uncontrolled studies ("ClearLight Therapy System," Med. Lett. 45:50, 2003)--But expensive!
• Benzoyl Peroxide
• Azelaic acid (Azelex)
• Topical antibiotics (active against Propionibacterium acnes
  • Erythromycin
  • Clindamycin
  • Sulfacetamide (Klaron)
• Topical retinoids (anti-inflammatory and comedolytic); can cause erythema, dryness, scaling, and pruritis; can be photosensitizine; contraindicated in pregnancy
  • Tretinoin (Retin-A) 0.025%-0.1% gel or cream
  • Adapalene (Differin) 0.1% gel
  • Tazarotene (Tazorac) 0.1% gel or cream QD--More effective than tretinoin 0.025% gel in one comparative trial (Cutis 67s:4, 2001--cited in Med. Lett. 44:52, 2002)
• Systemic antibiotics-Have anti-inflammatory properties as well as direct effects on bacteria; may not improve (or may worsen) for first 6-8wks; consider continuing for at least 6mos to reduce likelihood of antimicrobial resistance; consider stepping down to topicals at that point if acne under control
  • Tetracyclines-Generally consider first-line; avoid in pregnancy or in children < 8yo
    • Tetracycline 250-500mg Q6-12h
    • Doxcycline 100mg BID (don't neet to avoid administration w/food like tetracycline; can cause photosensitivity)
    • Minocycline 50-100mg BID (more effective against Propionibacterium acnes than tetracycline or doxycycline, but more expensive; may cause skip hyperpigmentation)
  • Macrolides, particularly erythromycin
  • Trimethoprim (with or without sulfamethoxazole)
• Isotretinoin PO (Accutane)
  • For severe, recalcitrant, nodulocystic or inflamamtory acne
  • Highly effective, but risk of adverse effects are high
  • Usually 0.5-1.0mg/kg/d x 20wks.
  • Potential adverse effects are dose-related and can be serious including teratogenicity, pseudotumor cerebri, vision impairment (when used in combination with tetracyclines), headaches, myalgias, dry skin, cheilitis, interactions with other drugs e.g. vitamin A and carbamazepine, and Ulcerative Colitis (Crockett SD et al., Am. J. Gasteroent. March 2010 e-publication ahead of printing)
• Oral Contraceptives in women may help, due to decrease in circulating androgens
• Oral antiandrogens (spironolactone, cyproterone) may help; latter not available in U.S. as of 2012; avoid in pregnancy

Treatment approaches:

• For mild-moderate acne, start with topical benzoyl perfoxide, +/- (retinoids, azleaic acid, or topical antibiotics)
• For mild-moderate acne unresponsive to above, or moderate-severe acne, consider systemic treatments starting with antibiotics

(Sources include Core Content Review of Family Medicine, 2012)