Transient localized cutaneous reaction after onabotulinumtoxinA aesthetic injection.

OnabotulinumtoxinA (ONA) is an injectable neurotoxin frequently used to temporarily halt the skin changes associated with aging. Side effects are rare and usually minor, such as bruising, injection site discomfort, and headaches. However, a true hypersensitivity reaction is a serious adverse effect, and clinicians should not attempt another trial if allergy is suspected. We present a case of a benign localized cutaneous reaction following ONA injections in the forehead without signs of an allergic reaction. The rash resolved with topical hydrocortisone, and the patient was able to undergo another trial of injections without recurrence.