What is the recommended management for an infected acne cyst?

Management of Infected Acne Cysts

For an infected acne cyst, immediately perform incision and drainage with culture, then initiate oral doxycycline 100 mg daily combined with topical adapalene/benzoyl peroxide and inject the lesion with intralesional triamcinolone acetonide (3.3–10 mg/mL) for rapid pain relief. 1, 2

Immediate Management

Drainage and Culture

• Perform prompt incision and drainage of any inflammatory cyst or abscess and obtain culture specimens to guide antibiotic selection 2, 3
• Culture typically grows Cutibacterium acnes in the majority of cases 3
• Incision and drainage combined with conservative acne management can prevent the need for surgical excision in many patients 3

Intralesional Corticosteroid Injection

• Inject large, painful cystic nodules with triamcinolone acetonide diluted to 3.3–10 mg/mL to achieve rapid inflammation reduction within 48–72 hours 4, 1, 2
• Use minimal injection volumes to minimize risk of skin atrophy, pigmentary changes, and telangiectasias 4, 1
• This provides immediate pain relief while systemic therapy takes effect 4

Systemic Antibiotic Therapy

First-Line Oral Antibiotic

• Doxycycline 100 mg once daily is the strongly recommended first-line oral antibiotic for moderate cystic acne 4, 1, 5
• Minocycline 100 mg once daily may be used as a conditional second-line alternative when doxycycline is not tolerated 4, 1
• Never use oral antibiotics as monotherapy—this rapidly induces bacterial resistance 4, 1

Duration and Monitoring

• Limit systemic antibiotics to a maximum of 3–4 months to minimize development of bacterial resistance 4, 1, 2
• Extending oral antibiotic therapy beyond this period without re-evaluation markedly increases resistance risk and antibiotic-associated complications 1, 2
• Clinical improvement is expected within 1–2 weeks of treatment initiation 5

Mandatory Concurrent Topical Therapy

Fixed-Dose Combination Retinoid + Benzoyl Peroxide

• All patients must receive a concurrent fixed-dose combination of adapalene 0.1–0.3% plus benzoyl peroxide 2.5–5% applied once daily in the evening 4, 1
• This addresses comedones, micro-comedones, and provides antimicrobial activity 1
• Concomitant benzoyl peroxide is mandatory to prevent development of antibiotic resistance 4, 1

Alternative Topical Option

• A fixed-dose clindamycin 1%/benzoyl peroxide 5% formulation can be used for additional inflammatory control 4, 1

Indications for Isotretinoin Escalation

When to Transition to Isotretinoin

• Initiate isotretinoin if the infected cyst does not respond after 3–4 months of appropriate triple therapy (oral antibiotic + topical retinoid + benzoyl peroxide) 1, 2
• Any evidence of active scarring should prompt immediate consideration of isotretinoin, regardless of acne severity 4, 1, 2
• Significant psychosocial burden or distress caused by acne is an indication for isotretinoin 4, 1
• Oral antibiotics alone are insufficient for severe cystic/nodular acne and may delay definitive isotretinoin therapy 1, 2

Isotretinoin Dosing

• Target cumulative dose of 120–150 mg/kg is required for durable remission 2
• Start at 0.5 mg/kg/day for the first month, then titrate to 1.0 mg/kg/day as tolerated 2
• In extremely severe disease, start isotretinoin concurrently with oral prednisone 0.5–1 mg/kg/day to prevent acne-fulminans-like eruptions 2

Hormonal Therapy for Female Patients

• In females with hormonal patterns (premenstrual flares, jaw-line distribution), add spironolactone 25–200 mg daily or a combined oral contraceptive to the regimen 4, 1
• Spironolactone does not require routine potassium monitoring in healthy patients without risk factors for hyperkalemia 4, 1

Critical Pitfalls to Avoid

• Never use topical or oral antibiotics without concurrent benzoyl peroxide—resistance develops rapidly 4, 1, 2
• Do not extend oral antibiotic courses beyond 3–4 months without re-evaluation; doing so dramatically raises resistance risk and complication rates 1, 2, 5
• Do not rely on oral antibiotics as the primary treatment for severe cystic acne with abscess formation—they delay definitive isotretinoin therapy 2
• Patients who fail to drain large cysts may require surgical excision, whereas those who undergo drainage typically heal completely with conservative management 3
• Adequate counseling about photosensitivity with doxycycline is essential 4, 5