Intralesional corticosteroid injections are less painful without local anesthetic: a double-blind, randomized controlled trial

Background Corticosteroid injections are a commonly used treatment for dermatologic pathologies. Although the injectable is often prepared with a local anesthetic, we hypothesize that patients receiving an injection with anesthetic will experience no decrease in pain at the time of injection. Methods Patients requiring a corticosteroid injection were prospectively randomized into two cohorts to receive a corticosteroid (triamcinolone acetonide) combined with either lidocaine with epinephrine 1:100 000 (anesthetic) or bacteriostatic normal saline. Both patient and clinician were blinded to the treatment arm. The primary outcome was pain associated with the injection measured using a Visual Analog Scale (VAS) immediately following the injection. Results Thirty-one patients were enrolled with 18 in the saline group and 13 in the lidocaine with epinephrine group. Pain scores were significantly higher for injections containing lidocaine with epinephrine versus saline (VAS 5.0 vs 2.0, p = .0056). Conclusions For various dermatologic pathologies, corticosteroid injections are effective and have relatively little associated pain. Counterintuitively, we found that there is more injection-associated pain when lidocaine with epinephrine is included with the corticosteroid. Therefore, clinicians should omit this anesthetic or dilute corticosteroids with normal saline, rather than with lidocaine and epinephrine. This will minimize injection pain as well as decrease the risk of pharmacologic adverse reactions from an unnecessary additional medication. Due to the small sample size, additional research may be necessary for generalization to other indications. Clinicaltrials.gov listing: NCT03630198

Automated summary

Corticosteroid injections are effective in treating dermatologic pathologies with relatively low associated pain. However, the study found that adding lidocaine with epinephrine to the injection may increase injection pain.