Evaluation of the sensation in patients with trigeminal post-herpetic neuralgia

Background: Post-herpetic neuralgia (PHN) is one complication after herpes zoster infection, which may affect the facial superficial sensitivity. Methods: Eighteen patients with PHN were interviewed and evaluated according to a systematized sensitivity approach, including mechanical, thermal and pain. Results: The pain location was V1 in 15 patients. All trigeminal branches from both facial sides were evaluated; we compared the affected with the opposite side. There was a significant difference at V1 with cold (P = 0.038), vonFrey (P = 0.008) and pinpricks (P = 0.022); at V2, the statistical difference occurred with cold (P = 0.034), heat (P = 0.019) and pinpricks (P = 0.037); at V3, differences occurred with cold (P = 0.042) and heat (P = 0.036). Only V1 and oral mucosa (V2-3) presented pain threshold differences between both sides (P = 0.001, P = 0.021). Conclusions: Age, predominance of trigeminal PHN in V1 and continuous burning pain was common and similar to literature. Sensation was hampered with evident deficits of all sensory modalities in the affected trigeminal areas, especially V1.