How Does Kenalog And 5-FU Work In Scar Injections?

Q: Dr. Eppley, I have a question regarding injectable scar treatments. What is the difference between 5-FU and Kenalog? What do each of them do to help a scar/scar tissue?

A: There are two types of scar injections that are currently available. The use of steroids, specifically triamcinolone (kenalog), is an historic and classic injectable approach. Triamcinolone is a synthetic corticosteroid that has a significant anti-inflammatory effect. It works on scars by either inhibiting or breaking down the cross-linking of collagen fibers, which is the backbone of scar formation. Dosing and frequency of Kenalog injections is critically important as it can have side effects such as soft tissue atrophy and tissue thinning. For this reason, lower doses are usually used, such as K10 rather than the more concentrated K40, and injections sessions should not be spaced more than 3 or 4 weeks apart.

5-FU is a well-known drug used as a chemotherapy agent against cancer for several decades. It works by inhibiting DNA replication which is important in stopping cancer cells which usually multiply faster than normal cells. In dermatology, 5-FU is most commonly used topically (as a cream) for treating actinic (solar) keratoses and some types of basal cell cancers of the skin. (e.g., Efudex or Carac) It is thought that it works in scar problems because it blocks collagen synthesis which might help to control excessive scar formation. It does not have the side effects of corticosteriods but injections are still done only every month or so, mainly to see how it is working.

I often combine the two, Kenalog and 5-FU, as an injectble combination when either it is a known problematic scar or a scar that has failed to respond to Kenalog injections. It is unknown whether one is superior to the other as a primary scar therapy.

Dr. Barry Eppley


Is 5-FU Injections better Than Kenalog For Problematic Scars?

Q: Hi Dr. Eppley, I emailed you about a month ago about getting 5-FU injections for lumpy scar tissue underneath my nipple for a revision gynecomastia surgery I had about 4 1/2 months ago.  I have been really busy at work and unable to get time off to make an appt.  Last time you emailed me about a month ago you said I could schedule an appt. and possibly get a 5-FU or kenalog injection.  I would really like to do this but an injection of kenalog makes me nervous due to the possibility of skin atrophy and other side effects I have heard about.  I have heard that 5-FU mixed with a small amount of kenalog does not really carry these side effects and can work quite effectively.  I have to travel about two hours or so to get there so I just want to make sure that 5-FU injections are a possibility before I make the trip.  Also I have an issue about the scar I have from the surgery I had and I saw on your website that you deal with scar management.  I know that the scar I have is only 4 1/2 months old but it does not seem to be getting any better and I was wondering if there are any non-surgical procedures or techniques, such as laser therapy, that you specialize in that could help to minimize this scar?  Thank you for any help you may be able to give me.

A: We can certainly do 5-FU injections for scar therapy as that is an item I keep stocked her for injection treatments. While it is uncertain whether 5-FU is really better than Kenalog, it does have a higher safety profile. Kenalog done judiciously (low dose), however, can be done without significant side effects as well. As for scar management, there are numerous options regarding non-surgical approaches depending upon the scar issue such as hypertrophy or redness. Most commonly we do pulsed light therapy (Broad Band Light, BBL) or laser treatments. That decision would have to be made at the time of examination.

Dr. Barry Eppley

Indianapolis Indiana

Will 5-FU Injections Help My Gynecomastia Scar Tissue Build-Up?

Q:  Hi Dr. Eppley, I recently had a revison gynecomatia surgery to remove scar tissue about 3 months ago and now I have even more scar tissue buildup than I had before. I have a big lump under my left nipple and was wondering if I it was possible to get 5-FU injections to reduce the scar tissue because I heard that Kenalog can have significant side effects. My doctor does not offer 5-FU and I have heard that this needs to be injected within the first few months after surgery to have an effect so I would like to get this done if possible. I would appreciate hearing back from you and helping me out with this if possible. Thank you!

A: At this early point after your revisional surgery, it is reasonable to consider a non-surgical treatment for your recurrent scar tissue. If significant improvement was to occur, you should be seeing it by now. The standard injectable scar treatment is Kenalog. While there are potential side effects (fat and skin atrophy), these are very much dosage and location dependent. High and frequent injections of Kenalog in skin level scars can cause these problems. But low doses of Kenalog done judiciously for subcutaneous fibrosis is unlikely to create these potential problems.

5-FU scar injections are useful in scar issues that have proven resistant to Kenalog. While there is nothing wrong with using it as a first choice therapy, it may or may not be necessary. When administered it is mixed with either a small amount of Kenalog or local anesthetic since there is definite burning afterwards associated with 5-FU injections. You are correct in assuming that these injections should be done early as they work best when new scar tissue is forming as opposed to long-stand established scar tissue.

Dr. Barry Eppley

Indianapolis, Indiana