Long Lasting Impairment of Taste and Smell as Side Effect of Lithium Carbonate in a Cluster Headache Patient.

BACKGROUND: Preventive treatment with lithium carbonate is a therapeutic option for chronic cluster headache. Lithium can lead to a broad spectrum of severe side effects, many of which are generally unknown. CASE DESCRIPTION: One week after starting treatment with lithium, a 55-year-old man with chronic cluster headache noticed a strange and unpleasant taste of various foods and a diminished smell. After 4 weeks, he decided to stop the therapy because of these complaints, but 9 months later both taste and smell still had not returned to normal. DISCUSSION: We present the first description of long-lasting dysgeusia and hyposmia as a side effect of lithium therapy in cluster headache. Dysgeusia has only rarely been reported as a side effect of lithium in other conditions and hyposmia has not previously been reported. Physicians should be aware of this rare, but severe, side effect when prescribing lithium.