Acquired Localized Hypertrichosis Induced by Rivastigmine

The document reports a case of acquired localized hypertrichosis, which is an unusual side effect characterized by excessive hair growth, in an 80-year-old Caucasian male with Alzheimer's disease after starting treatment with rivastigmine, a drug used for symptomatic treatment of Alzheimer dementia and Parkinson’s disease. Rivastigmine is known to inhibit acetylcholinesterase and butyrylcholinesterase and generally has an adequate safety profile with rare cutaneous side effects. However, this patient developed localized hypertrichosis on both forearms one month after beginning oral rivastigmine therapy. The document suggests that acetylcholinesterase inhibitors like rivastigmine can induce hair growth, as seen in the patient's response and supported by the hair growth activity associated with norgalanthamine, which also promotes the proliferation of dermal papilla.