No Laughing Matter: Gelastic Migraine and Other Unusual Headache Syndromes.

Primary and secondary headache disorders have established diagnostic criteria in the International Classification of Headache Disorders IIIb, as well as classic findings, which although not part of the formal criteria are often suggestive of a particular diagnosis. At times, headache disorders can involve unusual symptoms that lack an identifiable secondary cause. This review will discuss some of these unusual symptoms, including headache associated auditory and olfactory symptoms, as well as two case reports involving gelastic migraine and migrainous thoracalgia.