Alice in Wonderland Syndrome, Burning Mouth Syndrome, Cold Stimulus Headache, and HaNDL: Narrative Review.

BACKGROUND: Unusual headache syndromes are not as infrequent in clinical practice as was generally believed. About three fourths of the classified headache disorders found in the ICHD-II can be considered rare. OBJECTIVE: The aim of this narrative review was to perform a literature review of the pathophysiology, clinical presentation, diagnostic criteria, and treatment of the following unusual headache disorders: Alice in Wonderland syndrome, burning mouth syndrome, cold stimulus headache, and the syndrome of transient headache and neurologic deficits with cerebrospinal fluid lymphocytosis. METHOD: A literature review was performed using PubMed for each of the abovementioned headache disorders. CONCLUSION: The unusual headache syndromes as a distinct group of disorders are not as infrequent in clinical practice as was generally believed. Some of them, albeit considered as unusual, may occur with relative frequency, such as cold stimulus headache and burning mouth syndrome.