Hypertrophic Scars & Keloids
What Are Hypertrophic Scars and Keloids?
A scar that forms after a wound from an injury has closed over, or after a sutured surgical wound has knitted together, is reddish for a while. A red scar usually changes into a white scar over time, over a span of several months to several years.
However, if something goes wrong with the wound’s healing, instead of turning white it can stay red and the scar can become thick and raised. When the original wound area becomes red and raised it is called a hypertrophic scar, and when it becomes red and raised beyond the area of the original wound it is called a keloid. A keloid can be uncomfortable, causing pain or itching. That said, the size of the original wound is often unknown at the time of examination, and there does not seem to be much point in distinguishing between the two. (The Japanese guidelines do, however, distinguish them.)
Treatment of Hypertrophic Scars and Keloids
First, if there appears to be a cause that prolongs inflammation, such as a foreign body, we remove it.
Topical steroids
A steroid topical medication is applied once or twice a day. There is also a method of replacing a steroid tape once a day. Because the skin thins where the medication contacts normal skin, care is needed not to apply it beyond the area or let the tape shift.
Local steroid injection
When topical treatment has little effect, we inject a steroid. This is done about once a month. Injecting too much carries a risk of the skin thinning so that red blood vessels stand out more, the skin becoming thin, or the area becoming sunken. An allergic reaction to additives in the medication can also occur.
Oral medications
We prescribe an antiallergic drug called Rizaben (tranilast) and a Kampo (Japanese herbal) medicine called Sairei-to, which has an anti-inflammatory action. Rizaben has side effects such as eosinophilic cystitis and impaired liver function, and Sairei-to has the side effect of low blood potassium (hypokalemia).
Local Botulinum Toxin Injection (self-pay)
Injecting botulinum toxin, which is used for things like smoothing wrinkles, into the skin can improve the redness and raised appearance of a keloid. The proposed mechanisms are an action that suppresses fibrosis and a reduction in tension on the wound due to decreased muscle tone.
In terms of efficacy, the data show that improvement in redness and thickness is equivalent to local steroid injection, and improvement in itching and pain appears to be slightly better than with steroids. Side effects such as skin atrophy and dilated capillaries, meanwhile, are more common with steroids. These studies make a somewhat unfair comparison because the frequencies differ, steroids once a month versus botulinum toxin once every six to eight weeks, but reports that align both to once a month show similar results.
There are also reports that combining botulinum toxin with a steroid gives better results than either alone. Many studies administer the two drugs on the same day, but in practice, when the scar is hard the injection does not go in well, so our clinic recommends administering them on separate days. Note that when botulinum toxin and steroid are used in combination, the steroid administration is also self-pay.