What are the different types of acne and their respective treatments?

Types of Acne and Their Treatments

Classification of Acne Types

Acne vulgaris is classified by lesion morphology into comedonal, inflammatory, mixed, and nodulocystic types, with severity grading (mild, moderate, severe) determining treatment intensity. 1, 2

Lesion-Based Classification

• Comedonal acne consists of open comedones (blackheads) and closed comedones (whiteheads) without significant inflammation 1, 3

• Inflammatory acne presents with papules, pustules, and inflammatory lesions with redness and tenderness 1, 3

• Mixed acne combines both comedonal and inflammatory lesions, representing the most common presentation 4

• Nodulocystic acne (also called cystic or severe acne) features large, painful nodules and cysts extending deep into the dermis with high scarring risk 5, 4

Severity-Based Treatment Algorithm

Mild Acne (Few Comedones and Papules)

The American Academy of Dermatology recommends topical retinoid (adapalene 0.1-0.3% or tretinoin 0.025-0.1%) combined with benzoyl peroxide 2.5-5% as first-line therapy. 2

• Adapalene 0.1% is available over-the-counter and has superior tolerability compared to other retinoids 2

• Benzoyl peroxide prevents bacterial resistance and provides antimicrobial effects without resistance development 2

• Azelaic acid is particularly useful for patients with post-inflammatory hyperpigmentation 2

• Topical dapsone 5% gel is effective for inflammatory acne, especially in adult females, without requiring G6PD testing 2

Moderate Acne (Numerous Comedones and Inflammatory Lesions)

Fixed-dose combination products containing topical retinoid + benzoyl peroxide ± topical antibiotic (clindamycin 1% or erythromycin 3%) are recommended. 2

• Topical antibiotics must always be combined with benzoyl peroxide—never use as monotherapy due to rapid resistance development 2, 6

• Fixed combinations (clindamycin 1%/BP 5%, erythromycin 3%/BP 5%) enhance compliance 2

• Salicylic acid 0.5-2% provides over-the-counter comedolytic effects for resistant cases 2

Moderate-to-Severe Inflammatory Acne

Triple therapy with oral antibiotics + topical retinoid + benzoyl peroxide is first-line treatment. 2

• Doxycycline 100 mg daily is strongly recommended as the preferred oral antibiotic (moderate evidence) 2, 5

• Minocycline 100 mg daily is conditionally recommended as an alternative 2

• Sarecycline is a newer tetracycline option with targeted antimicrobial activity 2

• Limit systemic antibiotics to 3-4 months maximum to prevent bacterial resistance 2, 5

• Subantimicrobial doxycycline (20 mg twice daily to 40 mg daily) provides anti-inflammatory effects without antimicrobial resistance risk 2

Severe Nodulocystic/Cystic Acne

Isotretinoin 0.5-1.0 mg/kg/day targeting cumulative dose of 120-150 mg/kg is the definitive treatment, as it addresses all four pathogenic factors of acne. 2, 5

• Indications include severe nodular acne, treatment-resistant moderate acne after 3-4 months of appropriate therapy, any acne with scarring, or significant psychosocial burden 2, 5

• Daily dosing is preferred over intermittent dosing 2

• Monitor liver function tests and lipids at baseline and during treatment—CBC monitoring is not needed in healthy patients 2

• Population studies have not identified increased risk of depression or inflammatory bowel disease 2

• Mandatory pregnancy prevention through iPledge program for persons of childbearing potential 2, 5

• Intralesional triamcinolone acetonide 10 mg/mL (diluted to 5 or 3.3 mg/mL) provides rapid relief for individual large nodules within 48-72 hours 2, 5

Hormonal Acne (Female Patients)

Combined oral contraceptives and spironolactone are effective hormonal therapy options for females with hormonal acne patterns or premenstrual flares. 2, 6

• Combined oral contraceptives reduce inflammatory lesions by 62% at 6 months 2, 4

• Spironolactone 25-200 mg daily (typically starting at 50-100 mg) is particularly useful for patients who cannot tolerate or prefer to avoid oral antibiotics 2, 6

• No potassium monitoring is needed in healthy patients without risk factors for hyperkalemia 2, 6

• Endocrine testing (free and total testosterone, DHEA-S, androstenedione, LH, FSH) is warranted only for patients with signs of hyperandrogenism 6

Maintenance Therapy After Clearance

Continue topical retinoid monotherapy (adapalene 0.1-0.3% or tretinoin 0.025-0.1%) indefinitely to prevent recurrence. 2, 5

• Benzoyl peroxide can be continued as adjunctive maintenance therapy 2

Critical Pitfalls to Avoid

• Never use topical or oral antibiotics as monotherapy—resistance develops rapidly without concurrent benzoyl peroxide 2, 5, 6

• Never extend oral antibiotics beyond 3-4 months without re-evaluation, as this dramatically increases resistance risk 2, 5

• Do not underestimate severity when scarring is present—this warrants aggressive treatment (isotretinoin) regardless of lesion count 2, 5

• Avoid applying tretinoin with benzoyl peroxide simultaneously due to oxidation inactivation—use adapalene instead or separate application times 2

• Counsel about photosensitivity with retinoids and doxycycline—daily sunscreen is mandatory 2, 5

• Do not apply retinoids to broken skin or active wounds 2