Lesser Occipital Neuralgia Secondary to Continuous Positive Airway Pressure (CPAP) Mask Headgear: A Case Report

Occipital neuralgia is a well-characterised cause of unilateral head and neck pain arising from irritation of the greater or lesser occipital nerve (LON).External headwear (helmets, goggles, and tight headbands) is a recognised trigger of pericranial pain, formally classified by the International Classification of Headache Disorders (ICHD-3) as external-compression or external-traction headache.To our knowledge, lesser occipital neuralgia specifically attributed to continuous positive airway pressure (CPAP) mask headgear has not been previously reported.We report an 81-year-old man referred for a one-year history of right-sided cervicalgia and hemicranial headache, initially presumed to be spondylotic given multilevel cervical degenerative disc-osteophyte disease with severe foraminal stenosis on imaging.Only on closer review of the clinical history did the temporal relationship between symptom onset and initiation of nocturnal CPAP for obstructive sleep apnoea, together with hyperalgesia sharply confined to the territory of the LON and pain reproduced by axial rotation, point away from the presumed spondylotic cause and toward mechanical entrapment of the LON by the mask headgear.Pregabalin, physiotherapy, and mesotherapy directed at the presumed spondylotic/myofascial aetiology produced limited benefit.An ultrasound-guided anaesthetic block of the right LON, performed under aseptic technique, resulted in immediate and complete resolution of pain on cervical rotation, confirming the diagnosis.This case supports a mechanical, device-related aetiology of lesser occipital neuralgia in CPAP users, mediated by repetitive strap-related compression/traction over the nerve's course along the posterior border of the sternocleidomastoid muscle, aggravated by cervical rotation, and occurring even in the presence of confounding degenerative cervical spine disease.Clinicians should consider this diagnosis in CPAP users presenting with cervicogenic-type headache, and ultrasound-guided nerve block can serve as both a diagnostic and therapeutic tool.