Persistent idiopathic facial pain, a challenging diagnostic entity: clinical series from a third-level headache center

Background: Persistent idiopathic facial pain (PIFP) is a rare and disabling disease, often misdiagnosed. In this paper, we describe clinical phenotypes and histories of our patients with PIFP. Methods: Clinical information about pain, treatment histories, previous diagnoses, and MRI findings were assessed during the visit and collected retrospectively. Results: We observed a total of 44 females and 19 males, with a median age of 63 years. The patients had previously received diagnoses of trigeminal neuralgia, short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), and migraine, and some had a diagnosis of PIFP. The quality of pain was described mostly as continuous, stabbing, or burning. The distribution of the pain was referred to as the trigeminal territory, mostly with a second-third branch distribution. Eighteen patients underwent dentistry procedures before the pain started. Pregabalin and carbamazepine were the most frequently prescribed treatment. In 18 patients, a neurovascular conflict was found, and all underwent invasive procedures with poor outcomes. Conclusions: PIFP is a challenging orofacial pain entity, often misdiagnosed. Knowledge of the disease is the first step toward better management. A methodological and systemic approach like that applied to neuropathic pain would be suitable. We suggest a multidisciplinary approach, including medications combined with non-pharmacological options.