Fremanezumab-associated injection site alopecia.

Area of Science:

• Neurology
• Dermatology
• Pharmacology

Background:

• Calcitonin gene-related peptide (CGRP) inhibitors are a novel class of injectable monoclonal antibodies for migraine prevention.
• Clinical trials show efficacy and good tolerance, but post-marketing surveillance has noted alopecia as an adverse event.
• Most reported cases link scalp alopecia to erenumab, with less data on fremanezumab and injection site-specific alopecia.

Purpose of the Study:

• To report a case of persistent, localized injection site alopecia.
• To investigate a potential link between fremanezumab use and lower extremity alopecia.
• To explore the possible mechanism of CGRP's role in hair follicle immune privilege.

Main Methods:

• Case report from a headache clinic.
• Patient administered fremanezumab for migraine prevention.
• Observation and documentation of localized alopecia at injection sites.

Main Results:

• A patient developed persistent, localized alopecia on the lower extremities following fremanezumab injections.
• This contrasts with previously reported scalp alopecia associated with other CGRP inhibitors.
• The findings suggest a potential for injection site-specific adverse effects.

Conclusions:

• Fremanezumab, a CGRP inhibitor, may cause localized injection site alopecia.
• Hair follicle immune privilege failure, due to CGRP's immunomodulatory effects, is a potential mechanism.
• Further research is needed to understand the full spectrum of CGRP inhibitor-related alopecia.