Secondary nummular headache: Are they more common than we thought?

Area of Science:

• Neurology
• Headache Medicine
• Clinical Neuroscience

Background:

• Nummular headache (NH) is typically primary, but secondary causes exist, presenting diagnostic challenges.
• Distinguishing primary from secondary NH is crucial for effective, targeted treatment strategies.
• Understanding the etiology of NH is essential for patient management.

Purpose of the Study:

• To comprehensively describe symptomatic nummular headache (NH).
• To compare the characteristics of symptomatic NH with primary NH cases.
• To identify factors differentiating primary and secondary NH.

Main Methods:

• Retrospective monocentric study of 131 patients diagnosed with NH (2002-2022).
• NH cases classified using International Classification of Headache Disorders (ICHD-2, ICHD-3) criteria.
• Causality for symptomatic NH established based on temporal relation and response to treatment; cases categorized as 'definite' or 'probable'.

Main Results:

• 34 patients (25.9%) had symptomatic NH, including post-traumatic, cranial bone disorders, intracranial neoplasia, and vascular malformations.
• Symptomatic NH patients were more likely to have a history of previous headache (52.9% vs 29.9%) and remote head trauma (26.5% vs 9.3%).
• Preventive treatment was significantly more effective in symptomatic NH (72.2% vs 30.3%) when cause-specific treatment was applied.

Conclusions:

• Symptomatic nummular headache (NH) is a frequent diagnosis.
• A history of previous headache or remote head trauma may indicate symptomatic NH.
• Neuroimaging is essential for all NH cases due to potential intracranial pathologies, and identifying the cause is vital for effective treatment.