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Pathophys and Cause

Cause:Hormonal changes of puberty; bacterial (corynebacterium acne)?,, iodides and bromides

Pathophys:Hypertrophic sebaceous glands lead to increased sebum production and desquamation, especially with androgen stimulation, w comedone formation; sebum undergoes lypolysis by bacteria, which, in turn, causes inflammation. Cystic acne is associated with increased androgen levels from partial adrenal 2I-OH deficiency or polycystic ovaries, hence low-dose dexamethasone and/or birth control pills help (Nejm 1983;308:981)

Epidemiology

Teenagers; XYY genotype may correlate w severe acne vulgaris and early age of onset (Ann IM 1970;73:270); associated with seborrheic dermatitis

Signs and Symptoms

Sx:Acne; iodide and bromide types lack comedones and may be in unusual places

Si:Papules on erythematous base, pustules, comedones, nodules, cysts, scars

Complications

HIDRADENITISin axilla or groin, rx with topical and systemic antibiotics, and antibacterial soaps, intralesional steroids; birth control pills occasionally helpful. Avoid I + Ds; rx severe cases with excision of apocrine gland-bearing skin

r/o ACNE ROSACEA(Nejm 2005;352:793), which is central facial; has telangiectases, papules, and pustules without comedones or scarring; rx with dietary vasodilator restriction, topical rx with metronidazole 0.75% cream bid (Med Let 1989;31:75), azelaic acid 15% gel bid, and po tetracycline (Med Let 2007;49:5) w strict photo protection, as below

Treatment

Rx:

(Nejm 2005;352:1463; Jama 2004;292:726)

Mild:

Moderate:

  • Oral antibiotics:
    • Tetracycline (Med Let 2007;49:5) 250-500 mg po bid ($6/mo) until better, then qd and taper, or doxycycline 100 mg po bid ($25/mo) or minocycline 100 mg po bid ($50/mo), of its long-acting once a day form (Solodyn) ($500/mo); because of sunburn, use sunscreen or stop in summer, especially w doxycycline (Nejm 1976;294:43); beware of pregnancy in women since stains infants’ teeth
    • Clindamycin po as good or better but higher C. diff colitis risk
    • Erythromycin also works
    • Azithromycin 250 mg po biw-tiw or less, expensive
  • Antiandrogens
  • Narrow band blue light (clear light is ineffective) (Med Let 2003;45:50)
  • Handheld heat devices (Med Let 2007;49:51)

Severe/cystic:

  • Retinoids:
    • Isotretinoin (Accutane) (Med Let 2002;44:82) 1-4 mg/kg po qd × 5 mo after derm consult; $100+/mo; 95% remissions; adverse effects (FDA Bull 13:21): 33% teratogen in 1st trimester (Nejm 1985;313:837), difficult to obtain for potentially pregnant women (Nejm 1989;320:1007); elevated uric acid; regional ileitis; corneal opacities; elevated lipids may cause atherosclerosis (Nejm 1985;313:981); pseudotumor cerebri; hyperostosis, at least at higher doses, which are used in ichthyosis (Nejm 1983;308:1012); arthritis and fatigue limit use in athletes (R. Kenney 12/85); possibly depression and suicide
    • Acitretin (Soriatane) (Rx Let 1997;4:64) po qd; less long-acting metabolites than isotretinoin but alcohol counteracts this advantage by converting it to those toxic forms
  • Low-dose dexamethasone, with or without birth control pills (Nejm 1983;308:981)
  • Intralesional steroids
  • Cryotherapy