What are the guidelines for steroid (corticosteroid) injections, including indications and contraindications, for the treatment of acne and keloids?

Guidelines for Intralesional Corticosteroid Injections for Acne and Keloids

Intralesional triamcinolone acetonide is recommended 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

Indications

For Acne

• Inflammatory nodulocystic acne - particularly for larger acne papules or nodules 1
• Acne keloidalis - inflammatory follicular lesions 1
• Occasional or particularly stubborn cystic lesions - not effective as a primary strategy for patients with multiple lesions 1
• Patients at risk of acne scarring requiring rapid improvement in inflammation and pain 1

For Keloids and Hypertrophic Scars

• Hypertrophic scars and keloids of any etiology 1, 2
• Recurrent keloids after surgical excision 3, 4
• Cosmetically sensitive sites where other treatments have failed 3

Dosing Protocols

For Acne Lesions

• Nodular acne: Triamcinolone acetonide 10 mg/mL, may be diluted with sterile normal saline to 5 or 3.3 mg/mL 1
• Acne keloidalis: Triamcinolone acetonide 10 mg/mL into inflammatory follicular lesions 1
• Injection technique: 0.05-0.1 mL per injection produces a tuft of response about 0.5 cm in diameter 1
• Expected response: Flattens most acne nodules in 48 to 72 hours 1

For Keloids and Hypertrophic Scars

• Standard concentration: Triamcinolone acetonide 40 mg/mL into hypertrophic scars and keloids 1
• Alternative concentrations: 5-10 mg/mL may be used depending on lesion characteristics 1
• Injection depth: Just beneath the dermis in the upper subcutis 1
• Frequency: Monthly injections until adequate response achieved 1, 3
• Combination therapy: May be combined with 5-fluorouracil (50 mg/mL) in 1:1 ratio for enhanced efficacy and reduced side effects 5, 4

Absolute Contraindications

Do not inject at sites with:

• Active infections such as impetigo or herpes 1
• Previous hypersensitivity to triamcinolone or any components 1, 6
• Active tuberculosis or systemic fungal infection (for large injections) 1, 6

Systemic contraindications for extensive use:

• Extensive plaque psoriasis, pustular psoriasis, or erythrodermic psoriasis 1
• Active peptic ulcer disease 1, 6
• Uncontrolled diabetes, heart failure, or severe hypertension 1
• Severe depression or psychosis 1
• Idiopathic thrombocytopenic purpura (for intramuscular preparations) 6

Relative Contraindications and Precautions

• Unstable joints - intra-articular injection generally not recommended 6
• Congestive heart failure, hypertension, or renal insufficiency - use with caution due to sodium retention and potassium loss 6
• Cirrhosis - enhanced corticosteroid effects 6
• Osteoporosis risk factors - corticosteroids decrease bone formation 6

Adverse Effects and Risk Mitigation

Local Complications (Most Common)

• Skin atrophy - occurs in 44% with triamcinolone alone 5
• Pigmentary changes - both hypopigmentation and hyperpigmentation 1
• Telangiectasias - occurs in 50% with triamcinolone 5
• Hypertrichosis (excessive hair growth) 1

Prevention Strategy

Use lower concentration and volume of corticosteroid to minimize local adverse events 1. Decreasing concentration from 40 mg/mL to 10 mg/mL or diluting to 5 mg/mL significantly reduces atrophy risk 1.

Systemic Complications (With Repeated Injections)

• Hypothalamic-pituitary-adrenal axis suppression 1
• Anaphylaxis, angioedema, and urticaria (rare) 1
• Contact allergic dermatitis from benzyl alcohol preservative 1
• Sterile abscess formation 1
• Steroid acne (paradoxical) 1

Infection-Related Risks

• Impaired wound healing 1, 6
• Increased infection risk at injection sites 1
• Septic arthritis if injected into infected joints 6

Clinical Efficacy and Outcomes

For Acne

• Efficacious for occasional stubborn cystic lesions but not effective as primary treatment for multiple lesions 1
• Rapid symptom relief within 48-72 hours 1
• Should be used judiciously in patients at risk of scarring 1

For Keloids

• Variable response: 50-100% regression reported 3
• Recurrence rates: 33% at 1 year, 50% at 5 years 7, 3
• Combination therapy superior: Triamcinolone plus 5-fluorouracil shows better outcomes with fewer side effects than either agent alone 5, 4
• Faster response than verapamil but with higher complication rate 3

Common Pitfalls to Avoid

• Injecting too superficially - increases risk of atrophy and pigmentary changes 1
• Using excessive concentration or volume - dramatically increases adverse effect risk 1
• Treating multiple acne lesions - not an effective strategy; reserve for isolated stubborn nodules 1
• Monotherapy for keloids - combination approaches yield better long-term results 3, 5, 4
• Injecting into infected sites - must exclude septic process before injection 6