Pearls & Oy-sters: Trigeminal neuropathy associated with herpes labialis

CASE REPORT A previously healthy 41-year-old woman with recurrent herpes labialis since her 20s noticed a herpes labialis lesion on the left side of the lower lip. After 2 days, she experienced the acute onset of tingling and a swollen sensation of the left side of the face, beginning at the V3 division of the trigeminal nerve and progressing to involve the V1 and V2 divisions over the course of 2 days. A dermatologist diagnosed herpes labialis and prescribed acyclovir 1,000 mg in 2 divided doses for 5 days. However, the symptoms did not improve after the lesion disappeared. The left side of the tongue perceived a bitter taste 8 days after the onset of symptoms. Examinations on the following day revealed decreased pinprick, temperature, and light touch sensations in the 3 divisions of the left trigeminal nerve, as well as tingling and a swollen sensation in the affected region. A swollen sensation was also present in her inner cheek. Corneal reflexes and trigeminal motor function were normal. The results of other neurologic examinations were normal. T2-weighted MRI revealed a hyperintense lesion, corresponding to the left STNT (figure, A and B). The lesion was surrounded by edema and showed slight contrast enhancement with gadolinium (figure, C). Examination of the CSF showed 0.7 cells/ L and a protein content of 22 mg/dL; herpes simplex virus (HSV) DNA was negative on PCR. After the diagnosis of trigeminal neuropathy associated with herpes labialis and treatment with IV methylprednisolone (1,000 mg) for 3 days, the lack of facial sensation improved rapidly, but slight tingling (especially in the V3 division) and dysgeusia remained. After that, the patient’s symptoms gradually resolved spontaneously and disappeared about 3 weeks after onset. T2-weighted images after resolution of all symptoms showed that the edematous lesion had disappeared, whereas the hyperintense lesion corresponding to the STNT partially remained (figure, D). Three months later, the patient had recurrence of a herpetic lesion on the opposite side of the lower lip, but did not experience trigeminal sensory disturbance at that time.