Pediatric nummular headache: review of the literature and a case series with nosographic considerations.

Background: Nummular headache (NH) is a rare, often underdiagnosed form of primary headache, characterized by pain localized to a well-circumscribed area of the scalp. Although well documented in adults, its presentation in pediatric age is still poorly understood and rarely described.

Methods: The narrative review synthesizes the few pediatric NH cases reported in the literature. Further we describe our small case series of six pediatric patients (age 9-17 years) diagnosed with NH. For each case, the following were evaluated: clinical features, age of onset, localization and form of pain, associated symptoms, family history, response to treatments and neuroradiological findings. Diagnoses were compared with ICHD-3 criteria and with data present in the literature.

Results: Five patients presented with episodic NH, one with a continuous form. The painful area ranged from 1 to 4 cm in diameter, with round, oval and rectangular shapes. Four reported migraine-like symptoms. In one case NH was secondary to Langerhans cell histiocytosis. In two patients, a rectangular-shaped area of pain was observed, suggesting the need to review the diagnostic criteria.

Conclusions: This case series highlights the clinical heterogeneity of NH in pediatric age, with episodic and continuous forms, morphological variability and migraine-like symptoms. The rectangular shape found in some cases calls into question the current nosographic limits and suggests the need for a broader pathophysiological understanding. Here we also propose possible new criteria for the diagnosis of Nummular Headache.