What is the best treatment approach for an adult male with acne on the chest and back?

Treatment for Adult Male Acne on Chest and Back

Start with adapalene 0.1% gel once nightly combined with benzoyl peroxide 2.5-5% gel once daily in the morning as first-line therapy for trunk acne, escalating to oral doxycycline 100 mg daily plus the topical regimen if moderate-to-severe inflammatory lesions are present. 1

Severity-Based Treatment Algorithm

For Mild Trunk Acne (Primarily Comedones and Few Inflammatory Lesions)

• Apply adapalene 0.1% gel once nightly to the entire affected area (chest and back) after washing and allowing skin to dry for 20-30 minutes, combined with benzoyl peroxide 2.5-5% gel once daily in the morning. 1, 2
• Adapalene 0.1% is the preferred initial retinoid due to superior tolerability, lack of photolability, and compatibility with benzoyl peroxide without oxidation concerns. 1
• Benzoyl peroxide 2.5% is equally effective as higher concentrations but causes significantly less irritation. 1
• This combination addresses both comedones (via adapalene) and provides antimicrobial activity (via benzoyl peroxide). 2

For Moderate Trunk Acne (Mixed Comedonal and Inflammatory Lesions)

• Add a fixed-dose combination topical antibiotic with benzoyl peroxide (clindamycin 1%/benzoyl peroxide 5% or 3.75%) applied once daily to the adapalene regimen. 1, 2
• Fixed-combination products enhance compliance and prevent antibiotic resistance when benzoyl peroxide is included. 1
• Never use topical antibiotics as monotherapy—resistance develops rapidly without concurrent benzoyl peroxide. 1, 2

For Moderate-to-Severe Inflammatory Trunk Acne (Numerous Papules, Pustules, or Nodules)

• Initiate triple therapy: oral doxycycline 100 mg once daily + topical adapalene + benzoyl peroxide, limiting systemic antibiotics to 3-4 months maximum. 1, 2
• Doxycycline 100 mg once daily is strongly recommended with moderate evidence as first-line oral antibiotic for trunk acne. 1, 2
• Minocycline 100 mg once daily is conditionally recommended as an alternative if doxycycline is not tolerated. 1, 2
• The large surface area of chest and back acne often necessitates oral antibiotics when inflammation is significant. 3

For Severe or Recalcitrant Trunk Acne

• Consider oral isotretinoin 0.5-1.0 mg/kg/day targeting cumulative dose of 120-150 mg/kg for severe nodular acne, treatment-resistant moderate acne after 3-4 months of appropriate therapy, or any acne with scarring. 1, 2
• Isotretinoin is the only drug affecting all four pathogenic factors of acne and is indicated when other therapies fail. 2
• Daily dosing is preferred over intermittent dosing. 1

Maintenance Therapy After Clearance

• Continue topical adapalene monotherapy indefinitely after achieving clearance to prevent recurrence. 1, 2
• Benzoyl peroxide can also be continued as maintenance to prevent new inflammatory lesions. 2, 4
• Topical retinoids are essential for long-term maintenance regardless of initial severity. 1

Practical Application Considerations for Trunk Acne

• Use a pea-sized amount of adapalene for each area (upper chest, lower chest, upper back, lower back) to ensure adequate coverage. 2
• Consider using body washes containing benzoyl peroxide or salicylic acid for large surface areas to improve ease of application. 2
• Adapalene 0.1% is available over-the-counter, making it highly accessible for initial treatment. 2, 5
• Apply products to clean, completely dry skin to minimize irritation. 5

Critical Pitfalls to Avoid

• Never use topical or oral antibiotics as monotherapy—resistance develops rapidly without concurrent benzoyl peroxide. 1, 2, 4
• Never extend oral antibiotics beyond 3-4 months without re-evaluation—this dramatically increases resistance risk. 1, 2, 4
• Do not underestimate severity when scarring is present, as this mandates more aggressive treatment regardless of lesion count. 1, 2
• Avoid applying traditional tretinoin formulations with benzoyl peroxide simultaneously due to oxidation (adapalene does not have this limitation). 2
• Recommend daily sunscreen use with retinoids due to photosensitivity risk. 2

Special Considerations for Adult Males

• Adult males with persistent trunk acne despite appropriate therapy should be evaluated for potential underlying endocrine disorders, though this is less common than in females. 6
• The severity-based treatment approach for trunk acne follows the same algorithm as facial acne. 2
• Large surface area involvement (chest and back) often requires systemic therapy earlier in the treatment algorithm compared to facial acne alone. 3