What is the recommended injection technique for intralesional triamcinolone in a patient with a history of acne presenting with keloid scars?

Injection Technique for Keloid Treatment

For keloid injection with triamcinolone acetonide, inject just beneath the dermis in the upper subcutis—not into the keloid substance itself—using a concentration of 40 mg/mL for hypertrophic scars and keloids. 1, 2

Anatomical Injection Depth

• Target the upper subcutis immediately beneath the dermis, avoiding injection directly into the keloid tissue itself 1, 2
• This technique ensures optimal drug distribution while minimizing the risk of injecting into deeper subcutaneous fat or causing tissue damage 2

Concentration Selection

• Use triamcinolone acetonide 40 mg/mL as the standard concentration for keloids and hypertrophic scars 3, 1, 2
• For facial keloids or areas at higher risk for atrophy, reduce the concentration to 10-20 mg/mL to minimize adverse effects 2
• This higher concentration (40 mg/mL) is specifically recommended for keloids, notably higher than the 10 mg/mL used for acne keloidalis 3, 1

Volume and Dosing Protocol

• Inject 0.05-0.1 mL per injection site, which produces a therapeutic effect in approximately 0.5 cm diameter area 2
• Multiple injection sites may be needed for larger keloids, spacing injections to cover the entire lesion 2
• Repeat injections every 3-4 weeks until the keloid flattens or symptoms resolve 1, 2

Pain Management Strategies

• Apply EMLA cream (lidocaine/prilocaine) as topical anesthesia 30-60 minutes prior to injection to minimize discomfort 2
• For young children or patients with extensive keloids requiring multiple injection sites, consider general anesthesia or sedation 2

Expected Outcomes and Treatment Duration

• Response to corticosteroid injection alone is variable, with 50-100% regression rates 4
• Be aware that recurrence rates are 33% at 1 year and 50% at 5 years 4
• After each injection, expect scar thickness reduction of approximately 0.81-1.24 mm 5
• Approximately 50% of cases show significant improvement in scar color, itching, and elevation 6

Critical Contraindications

• Do not inject at sites of active infection (impetigo, herpes) 3, 1, 2
• Avoid use in patients with previous hypersensitivity to triamcinolone 3, 1, 2
• Avoid large injections in patients with active tuberculosis or systemic fungal infections 3, 1, 2

High-Risk Situations Requiring Caution

• Exercise caution in patients with uncontrolled diabetes, heart failure, or severe hypertension 3, 1, 2
• Facial and intertriginous keloids carry higher risk for adverse effects—use lower concentrations (10-20 mg/mL) in these areas 1, 2
• Large or diffuse keloids present challenges with even distribution and increased systemic absorption risk 2

Common Adverse Effects to Monitor

• Local atrophy is the most consistent side effect—minimize risk by using appropriate concentrations and avoiding over-injection 1, 2, 7
• Monitor for pigmentary changes, telangiectasias, and hypertrichosis, which are dose-dependent 3, 1
• Ulceration, steroid acne, and menstrual cycle disturbances may occur, particularly at higher doses 5
• Repeated injections can suppress the hypothalamic-pituitary-adrenal axis 3, 1

Combination Therapy Considerations

• TAC combined with 5-fluorouracil is more effective and shows fewer side effects compared to TAC alone 4
• TAC combined with verapamil achieves statistically significant improvements with long-term stable results 4
• Laser therapy (CO2, pulsed-dye, or Nd:YAG) combined with TAC injections produces better results than laser alone 4