• botulinum toxin type A;
  • nummular headache;
  • allodynia

Objective.— We assessed the efficacy and safety of botulinum toxin type A (BoNTA; BOTOX®: Allergan, Inc., Irvine, CA, USA) in patients with nummular headache who did not respond to other treatments including nonsteroidal anti-inflammatory drugs (NSAIDs), local anesthetics, and/or gabapentin.

Background.— Nummular headache is characterized by circumscribed round or elliptical areas of fluctuating mild-to-moderate head pain in a chronic or remitting pattern. It is a relatively rare primary headache disorder that responds poorly to adequate treatment trials with local anesthetic, migraine, or neuropathic pain agents or NSAIDs.

Methods.— Four patients aged 35-58 years with intractable nummular headaches were given 25 units of BoNTA divided among 10 injection sites in and around the circumscribed affected areas of pain, paresthesia, and allodynia. All patients had 2 sets of injections approximately 14 weeks apart.

Results.— All patients met the International Headache Society criteria for nummular headache (International Classification of Headache Disorders, A13.7.1). Patients were female; mean age of onset was 42 years. Average disease duration prior to BoNTA treatment was 3.75 years. One patient reported concurrent episodic migraine and another reported concurrent tension-type headache. Patients reported round-shaped (n = 2; 6 and 3 cm in diameter), oval (n = 1; 4 × 2 cm), and elliptical (n = 1; 6 cm in length) areas of pain. Painful symptoms were reported in the right parietal convexity (n = 2) and the posterior frontal, unilaterally (n = 2). All patients experienced spontaneous or stimuli-triggered exacerbations and variable combinations of sensory disturbances, including allodynia, tenderness, and paresthesia. The temporal pattern was continuous in 3 patients and intermittent in one. Both the size and shape of the pain remained unchanged in all patients since the onset of nummular headache symptoms. Six to 10 days following BoNTA treatment, all patients experienced a reduction in nummular headache symptoms, which lasted approximately 14 weeks on average. Repeat injections gave the same degree of improvement. No treatment-related adverse events were reported.

Conclusions.— BoNTA appears to be a well-tolerated effective treatment for intractable, persistent nummular headache in patients with an inadequate response to other treatments including NSAIDs, gabapentin, or local anesthetics.