Acne

Mark Lebwohl, M.D.
Mt. Sinai School of Medicine

Definition/Key Clinical Features
Differential Diagnosis
Best Tests
Best Therapy
Best References

Definition/Key Clinical Features

• Characteristic skin lesions
  • Open and closed comedones
  • Erythematous papules
  • Pustules
  • Nodules
  • Cysts
  • Scars
• Most commonly affects face but can involve back and chest
• Earlier onset and increased severity in males
• Premenstrual flares common in females

Major Forms

Comedonal Acne

• Comedones
  • Keratinized cells
  • Sebum
• Predominance of open (blackheads) and closed (whiteheads) comedones

Inflammatory Acne

• Erythematous papules (3–10 mm)
  • Develop into pustules or resolve into fading erythematous macule
  • May cause postinflammatory hyperpigmentation
  • Pustules
  • Superficial, dry in a few days
• Nodules (≥ 1 cm)
  • Firm, erythematous, tender nodules becoming fluctuant or forming cysts
  • Fluctuant sinuses result in postinflammatory pigmentary changes and scarring

Clinical Variants

• Acne conglobata
  • Severe form with confluent large cysts, abscesses, and draining sinus tracts
• Acne cosmetica
  • Low-grade form resulting from use of greasy, occlusive cosmetics and lotions
• Acne excoriée
  • Large ulcers and erosions caused by picking of minor lesions
• Acne mechanica
  • From repeated trauma and rubbing (e.g., wearing sports helmets, shoulder pads, or bras)
• Pomade acne
  • Caused by thick oils in hair
• Neonatal and infantile acne
  • Erythematous papules and pustules lasting 2–6 mo after birth
  • May signal severe acne later in life

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Differential Diagnosis

• Folliculitis
• Milia
• Perioral dermatitis
• Chloracne
• Hidradenitis suppurativa
• Favre-Racouchot disease
• Rosacea

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Best Tests

• Diagnose by clinical features

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Best Therapy

• Depends on acne type and severity

Topical Therapies

Comedonal Acne

• Topical retinoids to unplug follicles and allow topical antibiotic and benzoyl peroxide penetration

Inflammatory Acne

• Treatment alternatives (by effectiveness)
  • Retinoids and benzoyl peroxide most effective
  • Topical antibiotics less effective but better tolerated
    • Can be used in combination with benzoyl peroxide (clindamycin 1% and benzoyl peroxide 5%)
    • Common regimen: antibiotic–benzoyl peroxide in morning and topical retinoid in evening
  • Azelaic acid
    • Can be used in combination with topical retinoids, benzoyl peroxide, or topical antibiotics
  • Sulfur-resorcinol lotion
  • Effective drying and peeling agent for treating individual lesions

Topical Drugs for Acne

Retinoids

• Most effective
• Adverse effects
  • Dryness
  • Irritation
  • Photosensitivity
• Adapalene
  • Dose: 0.1% gel q.d.
  • Cost/mo: 45 g/$95
• Tazarotene
  • Dose: 0.05% or 0.1% gel q.d.
  • Cost/mo: 30 g/$99
• Tretinoin
  • Dose: 0.01%–0.05% preparations q.d.
  • Cost/mo: 20 g/$45

Benzoyl Peroxide

• Most effective
• Adverse effects
  • Dryness
  • Irritation
• Dose: 2.5%–10% preparations b.i.d.
• Cost/mo: 45 g/$14

Antibiotics

• Clindamycin
  • Adverse effects
    • Antibiotic resistance
  • Dose: 1% preparation b.i.d.
  • Cost/mo: 30 g/$19
• Erythromycin
  • Adverse effects
    • Antibiotic resistance
  • Dose: 2% preparation b.i.d.
  • Cost/mo: 30 g/$18
• Erythromycin–benzoyl peroxide
  • Adverse effects
    • Dryness
    • Irritation
    • Contact dermatitis
  • Dose: 3% erythromycin, 5% benzoyl peroxide gel b.i.d.
  • Cost/mo: 46.6 g/$92
• Sodium sulfacetamide–sulfur
  • Adverse effects
    • Dryness
    • Irritation
    • Contact dermatitis
  • Dose: 10% sodium sulfacetamide, 5% sulfur lotion b.i.d.
  • Cost/mo: 30 g/$22

Azelaic Acid

• Adverse effects
  • Stinging
  • Irritation
• Dose: 20% cream b.i.d.
• Cost/mo: 30 g /$57

Sulfur and Resorcinol

• Adverse effects
  • Dryness
  • Peeling
  • Contact dermatitis
• Dose: 2% resorcinol, 8% sulfur preparation q.d. or b.i.d.
• Cost/mo: 28 g/$6

Salicylic Acid

• Adverse effects
  • Dryness
  • Irritation
• Dose: 0.5%–2% preparations q.d. or b.i.d.
• Cost/mo: 148 g/$6

Systemic Therapies for Nodulocystic Acne or Inflammatory Acne Unresponsive to Topical Therapy

Antibiotics: First-Line Therapy

• Long-term use of antibiotics for the treatment of acne may be associated with increased risk of breast cancer
• Doxycycline
  • Adverse effects
    • Photosensitivity
    • GI symptoms
    • Candidiasis
  • Dose: 50–100 mg p.o., b.i.d.
  • Cost/mo: $22
• Erythromycin
  • Adverse effects
    • GI symptoms
    • Candidiasis
  • Dose: 250–500 mg p.o., b.i.d.
  • Cost/mo: $17
• Minocycline
  • Adverse effects
    • GI symptoms
    • Candidiasis
    • Vertigo
    • Lupuslike syndrome (rare)
    • Hepatitis (rare)
  • Dose: 50 mg p.o., q.d., to 100 mg p.o., q.i.d.
  • Cost/mo: $77
• Tetracycline
  • Adverse effects
    • Photosensitivity
    • GI symptoms
    • Candidiasis
  • Dose: 250 mg p.o., q.d., to 500 mg p.o., q.i.d.; b.i.d. preferred
  • Cost/mo: $8
• Trimethoprim-sulfamethoxazole
  • Adverse effects
    • Bone marrow suppression
    • Drug eruption
  • Dose: 160 mg trimethoprim, 800 mg sulfamethoxazole b.i.d.
  • Cost/mo: $18
• Isotretinoin
  • Most effective agent; long-lasting remissions or cures; not used as first-line therapy because of serious potential adverse effects (teratogenicity, hyperlipidemia, cheilitis, alopecia, pyogenic granulomas, dry eyes, epistaxis, pseudotumor cerebri [rare]); limit treatment to 4–6 mo or refer
    • Central registry for physicians, pharmacists, and patients being established to prevent use during pregnancy
    • Dose: 0.5–1 mg/kg/day in 2 divided doses, to a cumulative dose of 120–150 mg/kg

Hormone Therapy

• Norgestimate–ethinyl estradiol
  • For women only; alternative to antibiotics and isotretinoin
  • Adverse effects
    • Thromboembolic disorders
    • Fluid retention
    • Hypertension
    • Breakthrough bleeding
    • Breast swelling and tenderness
  • Dose: 0.18 mg norgestimate, 0.035 mg ethinyl estradiol p.o., q.d., for 21 days; repeat q. 4 wk
  • Cost/mo: $30

Other Therapies

• Consider referral for the following:
  • Photodynamic therapy
  • Specialized abrasion therapy
  • Injections
  • Surgery

Therapy for Rosacea

• Avoid triggers such as alcohol, hot or spicy foods, or heat
• Sunscreens
• Laser therapy for telangiectasia
• Topical and oral antibiotics for papules and pustules, as for acne, but benzoyl peroxide less commonly used than for acne
• Azelaic acid for erythema

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Best References

Babilas P, et al: Photodermatol Photoimmunol Photomed 21:142, 2005

Mendelsohn AB, et al: Pharmacoepidemiol Drug Saf, May 12, 2005

Tan J: J Cutan Med Surg, Mar 31, 2005

Tan J, et al: Expert Opin Pharmacother 6:409, 2005

The author has received grants from Allergan Inc., Connetics Corp., Medicis, and Ortho-McNeil Pharmaceutical, Inc.

October 2005