Acne

Differential diagnosis

• Drug-induced acne
• Tropical acne - Extreme heat
• Acne aestivalis (Mallorca acne) - Sun exposure
• Rosacea - Late age onset, erythema, talengiectasia, papules, pustules, no comedones
• Periorificial dermatitis - Around mouth, nose or eyes sparing vermilion border
• Pseudo/Folliculitis, no comedones
• Keratosis pilaris - Follicular prominence and roughness (usually on arms, but may resemble acne on cheeks)
• Favre-Racouchot syndrome - Comedones on cheek due to sun damage

Treatment

Comedonal

1. Topical retinoids gel/cream (Tretinoin 0.025%, Adapalene 0.1%, Tazarotene 0.1%)
2. Benzoyl peroxide (BPO) 2.5% or 5% gel or Azelaic acid (AA) 20% cream (possible better tolerability than BPO)

Mild-moderate papulopustular

1. Topical Retinoid + BPO or Topical Abx + BPO
   • Adapalene 0.1% and BPO 2.5% (Tactupump)
   • Clindamycin 1% and BPO 5%
2. Treat with all three topicals (Retinoid, BPO, Abx) if no response x 3 months
3. Combined OCP or systemic antibiotics
   • High estrogen (ethinyl estradiol) concentration associated with decrease in inflammatory lesions
   • Tetracycline (eg. doxycycline 100mg PO BID or daily x 3-4 months)
     • Risk in pregnancy or <9yo (teeth discoloration/bone growth)
     • Side effects: GI, photosensitivity

Severe papulopustular

• Oral isotretinoin (pregnancy-prevention measures due to teratogenicity)
  • 0.5-1mg/kg daily divided BID for 15-20 weeks or
  • 0.5mg/kg daily divided BID for 1 month, then 1mg/kg/day divided BID, until a cumulative dose of 120-150 mg/kg
  • Consider lower dose 20mg every alternate day or 0.25-0.4mg/kg/day for moderate
  • Consider monitoring labs
    • Fasting lipid and LFTs at 4 weeks and 8 weeks, and then stop if normal

Other

• Oral zinc has been shown to have effect against inflammatory lesions
• Diet: Some evidence for low glycemic index diet, lack of evidence concerning dairy consumption
• Chemical peels have minimal evidence but are safe and inexpensive