Some patients with facial neuralgia respond favorably to vitamin B12 injections.
PHILADELPHIA—Vitamin B12 deficiency may cause isolated facial neuralgia, independent of trigeminal neuralgia and peripheral neuropathy, according to research presented at the 14th Congress of the International Headache Society. Treatment with B12 injections was found to alleviate the condition.
Jitendra K. Baruah, MD, and Gita R. Baruah, MD, presented a review of 17 patients (10 women; mean age, 55.4) who experienced frequent episodes of isolated unilateral facial neuralgic pain not typical of trigeminal neuralgia. A neurologic examination revealed that corneal and facial sensation, along with the strength of both facial and trigeminal nerve innervated muscles, were normal.
All patients reported a decrease in touch and pain sensation, as well as numbness on the affected side. The blink reflex and trigeminal nerve–evoked response were abnormal, and all subjects had low levels of serum B12 (average, 186.7 pg/mL; reference range, 300 to 900 pg/mL) and high levels of methylmalonic acid, indicating defective gastrointestinal absorption of vitamin B12, the researchers noted.
The patients received intramuscular or subcutaneous injections of 1,000 mcg vitamin B12, once a week for four weeks. The dose was subsequently tapered down to two-week intervals for eight weeks, and then once a month for a year, at which point patients will be re-evaluated.
Identifying and Treating Patients With Facial Neuralgia
The researchers observed the vitamin B12 deficiency during clinical evaluations of patients in their respective practices. “It was somewhat unexpected that vitamin B12 deficiency can cause isolated facial neuralgia,” Dr. Jitendra K. Baruah, a neurologist based in Milwaukee, told Neurology Reviews. “Treatment for facial neuralgia is sometimes very difficult, and patients may often go into multimodalities treatment without much success. Knowing that this condition is remediable with vitamin B12 therapy, it is important to identify these patients and treat them accordingly.”
The investigators also found that many patients with facial neuralgia also developed cold sores (herpes simplex labialis) on the site of the facial neuralgia, and the cold sores also responded to vitamin B12 treatment. “It may be possible that having cold sores means there is an active herpes simplex virus located in the gasserian ganglion, indicating that there may be some compromise of that particular side and these trigeminal nerves are found to be more susceptible to deficiencies to vitamins, such as B12,” Dr. Baruah explained.
—Rebecca K. Abma