to the editor: In the article on Dupuytren's disease, Drs. Trojian and Chu describe a procedure for injecting lidocaine 2% (Xylocaine) followed by triamcinolone acetonide (Kenalog) for the treatment of early disease. The accompanying footnote (“Lidocaine will precipitate triamcinolone; therefore, do not mix the two agents.”) caught me by surprise as I have been mixing these two agents in the same syringe for soft tissue and joint injections for many years without incident.

A survey of 835 rheumatologists found that 65.9 percent of them (and 74.7 percent of rheumatologists who trained after 1985) combine lidocaine and steroids for injection.¹ Textbooks describing soft tissue and joint injection technique also recommend combining lidocaine and a steroid in the same syringe.^2,3 The package inserts from steroid suspensions caution against mixing the steroid with lidocaine to avoid physical incompatibilities. Flocculation may be seen in the syringe when the parabens in multi-dose bottles of lidocaine are mixed with steroids.⁴ Although it is theorized that this precipitation may increase the risk of post-infection flare, this has not been proven. Using preservative-free, single-use vials of lidocaine may avoid precipitation in the syringe, but whether this influences the rate of post-injection flare has not been studied.

There are several potential advantages to combining lidocaine and a steroid in a single injection. Diluting the steroid in lidocaine may reduce the pain of injection. It also allows the medication to be distributed to a wider area and may decrease the risk of local skin atrophy. The addition of lidocaine to a steroid injection can add diagnostic information as in cases where it is injected subacromially for rotator cuff tendonitis.

Although some concerns about the effect of steroid precipitation on the risk of post-injection flares argue against combining steroids and lidocaine for soft tissue and joint injections, there is no evidence to discourage this common and useful practice.

editor's note: Dr. Schechtman is correct. The comment about not combining lidocaine and triamcinolone in the same syringe was added to the article during editing, based on unreferenced advice to this effect in an article on injecting the nodules of Dupuytren's disease.¹ Further investigation after receiving Dr. Schectman's letter leads us to conclude that this advice is unwarranted, and is indeed counter to the practice and experience of many of us. We apologize to Drs. Trojian and Chu for any embarrassment we may have caused. The footnote has been deleted from the online version of this article.

JAY SIWEK, MD, Editor