Neuropathic Characteristics In Patients With Persistent Idiopathic Facial Pain

BACKGROUND: Persistent idiopathic facial pain (PIFP) is a subtype of painful cranial neuropathies and other facial pains. The involvement of neuropathic mechanisms in PIFP, however, remains controversial. Using the Douleur Neuropathique 4 (DN4) questionnaire, the present study examined neuropathic characteristics in patients with PIFP. METHODS: The multi-institutional retrospective study collected the following clinical data from 205 consecutive patients with adult chronic pain: gender, age, BMI, diseases causing chronic pain, disease duration, visual analogue scale score of pain strength, and DN4 score. To compare neuropathic characteristics between PIFP and postherpetic neuralgia (PHN), we selected patients with PIFP (n=19) and patients with PHN (n=33), and performing a case–control study in which each patient with PHN or PIFP was matched by age and gender (n=16 in each group). RESULTS: DN4 score was significantly lower in the PIFP group than in the PHN group before and after matching. The incidence when DN4 was ≥4 was 10.5% before matching and 12.5% after matching in the PIFP group, both of which were significantly lower than those in the PHN group before and after matching (66.7% and 75.0%). CONCLUSION: Ten percent of the PIFP patients likely show neuropathic pain characteristics.