Intralesional Corticosteroid Injections for Acne and Keloids

Indications and Contraindications

The American Academy of Dermatology recommends intralesional triamcinolone acetonide as adjuvant therapy for inflammatory nodulocystic acne and as first-line treatment for keloids and hypertrophic scars, with specific dosing protocols and important contraindications to prevent complications 1, 2
Intralesional triamcinolone acetonide is indicated for inflammatory nodulocystic acne, particularly for larger acne papules or nodules, with a recommended dose of 10 mg/mL, which may be diluted with sterile normal saline to 5 or 3.3 mg/mL 1, 2, 3, 4
The treatment is also effective for acne keloidalis, with a recommended dose of 10 mg/mL into inflammatory follicular lesions 1
Patients at risk of acne scarring require rapid improvement in inflammation and pain, and intralesional triamcinolone acetonide is recommended as an adjuvant therapy 2

For nodular acne, the recommended dose is triamcinolone acetonide 10 mg/mL, which may be diluted with sterile normal saline to 5 or 3.3 mg/mL, with an injection technique of 0.05-0.1 mL per injection, producing a tuft of response about 0.5 cm in diameter 1, 3, 4, 5
For acne keloidalis, the recommended dose is triamcinolone acetonide 10 mg/mL into inflammatory follicular lesions 1
For hypertrophic scars and keloids, the standard concentration is triamcinolone acetonide 40 mg/mL, with alternative concentrations of 5-10 mg/mL depending on lesion characteristics, and an injection depth of just beneath the dermis in the upper subcutis 1, 4, 5

Local complications, such as skin atrophy, pigmentary changes, telangiectasias, and hypertrichosis, can occur, with skin atrophy occurring in 44% of patients treated with triamcinolone alone, and pigmentary changes, including both hypopigmentation and hyperpigmentation, also reported 1, 6
Systemic complications, such as hypothalamic-pituitary-adrenal axis suppression, anaphylaxis, angioedema, and urticaria, can occur with repeated injections, and the risk of impaired wound healing and increased infection risk at injection sites should be considered 1, 6
To minimize local adverse events, a lower concentration and volume of corticosteroid should be used, with decreasing concentration from 40 mg/mL to 10 mg/mL or diluting to 5 mg/mL significantly reducing atrophy risk 2, 7

Intralesional triamcinolone acetonide is efficacious for occasional stubborn cystic lesions, but not effective as primary treatment for multiple lesions, with rapid symptom relief within 48-72 hours 1, 3
The treatment should be used judiciously in patients at risk of scarring, with combination therapy showing better outcomes with fewer side effects than either agent alone 2, 7

Injecting too superficially increases the risk of atrophy and pigmentary changes, while using excessive concentration or volume dramatically increases adverse effect risk, and treating multiple acne lesions is not an effective strategy, with monotherapy for keloids yielding poor long-term results 1, 2, 6, 7