Clinical and pathophysiological description of nummular headaches: a case series

Nummular headache was initially described as an infrequent primary headache characterised by chronic circumscribed mild-to-moderate pain in a small area of the head that may present with exacerbations. Since its initial description, dozens of cases of nummular headache have been reported which broaden the clinical and pathophysiological spectrum. To review and establish the clinical characteristics of nummular headache, to analyse the epidemiology in our setting and to clarify some unanswered pathophysiological issues. The study involved 83 cases (42 women and 41 men) who were diagnosed with nummular headache from July 2008 and followed up until 2018 at the Fundacion Alcorcon Hospital. The mean age of onset was 46 years. The time to diagnosis was seven months. The pain was moderate-intense and oppressive, with exacerbations in 62.5% of cases. The average size of the symptomatic area was 2.4 ± 0.7 cm, with a parietal (47%), temporal (24%), frontal (12%) or occipital (6%) location. It presented a chronic (82%) or episodic (18%) pattern. Symptoms of local sensory dysfunction were observed in 25 patients and three others showed skin alterations. Spontaneous remission was observed in 36% of cases, and the most commonly used drugs were non-steroidal anti-inflammatory drugs, paracetamol and gabapentin. Botulinum toxin was effective. Nummular headache is a disorder with well-defined characteristics and is considered an entity in its own right. Our data indicate that its origin lies in the epicranial structures. The conjunction of pain, sensory dysfunction and trophic disorders suggests a local form of a complex regional syndrome.