What anesthetic should be given to a patient prior to intralesional injection of triamcinolone into a keloid scar?

Anesthetic for Intralesional Triamcinolone Injection into Keloid Scars

Topical lidocaine (60% lidocaine tape or EMLA cream containing lidocaine plus prilocaine) applied for at least 2 hours before injection is the most effective approach for reducing needle-stick pain during intralesional triamcinolone injection for keloid treatment.

Primary Recommendation: Topical Anesthesia

Topical lidocaine preparations should be the first-line anesthetic choice for intralesional keloid injections based on the following evidence:

• 60% lidocaine tape applied for ≥120 minutes before injection reduces pain scores from 82.6 mm to 18.9 mm on a 100-mm visual analog scale, with 71.4% of patients tolerating treatment well 1

• Topical anesthetics (EMLA cream or similar) significantly reduce needle-stick pain compared to no anesthesia or lidocaine mixing, particularly effective for sternum and auricular keloids 2

• The Infectious Diseases Society of America guidelines recommend EMLA cream (lidocaine plus prilocaine) as local anesthesia for intralesional injections, noting that young children may need general anesthesia for the procedure 3

Why NOT to Mix Lidocaine with Triamcinolone

Mixing 1% lidocaine with triamcinolone in a 1:1 ratio does NOT effectively reduce injection pain and should be avoided:

• A randomized controlled trial demonstrated that lidocaine mixed with triamcinolone failed to alleviate pain during the actual injection (VAS scores 4.97 for control vs 4.97 for lidocaine mixture) 2

• While lidocaine mixing reduces needle-stick pain slightly, it provides no benefit for the more significant injection pain that occurs during infiltration 2

• Diluting triamcinolone with lidocaine may reduce the effective concentration of corticosteroid delivered to the keloid tissue 4

Practical Application Protocol

For optimal pain control, follow this approach:

• Apply 60% lidocaine tape or EMLA cream to the keloid surface at least 2 hours before the procedure (ideally 2-4 hours) 1, 3

• Use occlusion to enhance penetration of the topical anesthetic 1

• Inject triamcinolone acetonide at 10-40 mg/mL concentration (typically 20 mg/mL for keloids) just beneath the dermis in the upper subcutis 5, 6

• Inject 0.05-0.1 mL per injection site to achieve therapeutic effect 5

• Repeat injections every 3-4 weeks as needed 5, 6

Important Safety Considerations

Monitor for local anesthetic toxicity when using topical preparations:

• Avoid applying topical lidocaine to large surface areas or for prolonged periods beyond recommended duration 3

• Be aware that anaphylaxis to triamcinolone acetonide can occur with repeated injections, even after years of uneventful use 7

• Common adverse effects include skin atrophy, telangiectasias, and pigmentary changes at injection sites, which are dose-dependent 5, 4

Alternative Considerations for Severe Cases

For patients who cannot tolerate the procedure despite topical anesthesia:

• General anesthesia may be necessary for young children or patients with extensive keloids requiring multiple injection sites 3

• Consider regional nerve blocks for keloids in anatomically appropriate locations, though this requires waiting 4 hours before or after any local anesthetic intervention 3