Acquired Localized Hypertrichosis Induced by Rivastigmine

Area of Science:

• Dermatology
• Pharmacology
• Neurology

Background:

• Hypertrichosis is excessive hair growth, which can be drug-induced and is typically reversible.
• Rivastigmine, an acetylcholinesterase inhibitor, is used for Alzheimer's and Parkinson's disease.
• Cutaneous side effects of rivastigmine are rare, with hypertrichosis not previously reported.

Purpose of the Study:

• To report a rare case of localized hypertrichosis secondary to rivastigmine treatment.
• To highlight a potential, unusual cutaneous side effect of acetylcholinesterase inhibitors.

Main Methods:

• Case report of an 80-year-old Caucasian male with Alzheimer's disease.
• Patient initiated oral rivastigmine therapy.
• Clinical observation of localized hypertrichosis on forearms.

Main Results:

• The patient developed localized hypertrichosis on both forearms one month after starting oral rivastigmine.
• This adverse event is hypothesized to be linked to rivastigmine's mechanism of action, potentially involving acetylcholinesterase inhibition and hair growth pathways.

Conclusions:

• Rivastigmine may induce localized hypertrichosis as an unusual adverse effect.
• Discontinuation of the causative agent is expected to resolve the hypertrichosis.
• Further investigation into the hair growth effects of acetylcholinesterase inhibitors is warranted.