Catarina Vasconcelos Fonseca, Alexandre Camões-Barbosa
Cervicogenic headache (CH) is a secondary headache disorder arising from cervical structures and is frequently associated with pain, disability, and reduced quality of life. Botulinum toxin type A (BoNT-A) has been proposed as a therapeutic option due to its muscle-relaxing and antinociceptive properties; however, its efficacy in CH remains uncertain. This review aimed to evaluate the current evidence regarding the use of BoNT-A in the treatment of cervicogenic headache. A literature search was conducted in the PubMed/MEDLINE and Scopus databases, and studies assessing BoNT-A in adults with CH were included. Data on study characteristics, injection protocols, clinical outcomes, and adverse events were extracted and qualitatively synthesized. Five studies met the inclusion criteria, comprising four randomized controlled trials and one prospective study. Considerable heterogeneity was observed in diagnostic criteria, toxin formulations, injection techniques, targeted muscles, and outcome measures. Most studies reported reductions in headache intensity and frequency following BoNT-A treatment, particularly in trigger point-guided protocols and chronic or treatment-resistant populations. The trapezius and splenius capitis were the most frequently targeted muscles. Nevertheless, one high-quality placebo-controlled trial found no significant benefit over placebo. Overall, BoNT-A was well tolerated, with no serious adverse events reported. Although several studies suggest potential benefits of BoNT-A for cervicogenic headache, the current evidence remains inconclusive. Further well-designed studies using standardized diagnostic criteria and injection protocols are needed to better define its therapeutic role.