Anesthesia dolorosa caused by penetrating cranial injury.

Anesthesia dolorosa (AD) is an uncommon complication of surgical treatments for trigeminal neuralgia. Its incidence is around 0.8%. To our best knowledge, AD caused by a penetrating cranial injury has not been reported previously. We report the case of a 31-year-old male patient with left-sided neuropathic keratitis and AD that began 18 years earlier, following a penetrating cranial injury with a knife to the left postauricular area. The patient was successfully treated by a carbamazepine and gabapentin combination. In conclusion, penetrating cranial injury is uncommon but may cause a serious neurologic disturbance. In the differential diagnosis of AD, a penetrating injury should be kept in mind. In these cases, treatments should be effective and immediate; otherwise, this may result in catastrophic consequences such as neurotrophic keratitis and blindness. Ophthalmologists should be aware of these potential problems.