Revisiting Persistent Idiopathic Facial Pain

PIFP is a rare condition with an incidence of 4.4 per 100,000 years and prevalence of 0.03%.^{1, 2, 3}

Eighty percent of patients with this condition attribute onset of symptoms to a dental treatment.⁴

1. Rozen TD. Relief of anesthesia dolorosa with gabapentin. Headache 1999;39: 761–2.
2. Benoliel R, Charly G. Persistent idiopathic facial pain. Cephalalgia 2017;37: 680–91. 
3. Mueller D, Obermann M, Yoon MS. Prevalence of trigeminal neuralgia and persistent idiopathic facial pain: a population-based study. Cephalalgia 2011;31: 1542–8.
4. Koopman JS, Dieleman JP, Huygen FJ. Incidence of facial pain in the general population. Pain 2009;147:122–7.

Patients describe an aching, throbbing, or burning type of pain. Pain is poorly localized, deep, and usually unilateral, with no evident disorder on the routine imaging studies.

An association has been established between the onset of symptoms and a previous dental treatment.¹

1. Headache Classification Committee of the International Headache Society (IHS). The international classification of headache disorders, 3rd edition (beta version). Cephalalgia 2013;33:629–808.

Diagnosis might involve an inferior alveolar nerve block or local infiltration with local anesthetic agent.

However, patients sometimes have an ambivalent response to this procedure, with occasional complete resolution of pain and, at other times, pain persisting.

Panoramic or periapical radiographs are used to rule out an odontogenic source of pain. MRN is being increasingly used for such patients. It is common to see entrapment neuropathy or evidence of prior peripheral trigeminal nerve injury, aiding in clarifying the cause in many such cases.

Use of low-dose anti-seizure medications (eg, gabapentin or tricyclic antidepressants) has proved effective in patient management. Topical medications, such as capsaicin have also shown some efficacy.