How common are treatment reactions?
With more than 500,000 people treated to date, only a small number of patients (approximately 1-2 percent) have developed an allergic reaction after one or more treatment injections. These reactions may consist of prolonged redness, swelling, itching and/or firmness at some or all injection sites. Most have lasted between three and four months, but in some cases have exceeded one year. In less than I% of treated patients, formation of a scab and sloughing (shedding) of the tissue at the treatment site have been noted, which can result in a shallow scar. On rare occasions, abscess formation has occurred at implantation sites. These reactions develop weeks to months following injections, and may result in scar formation.