Uncommon primary headaches.
OBJECTIVE
The new International Classification of Headache Disorders was recently published by the International Headache Society. Several uncommon primary headaches, including some new clinical entities (e.g. hypnic headache), were included in the section on 'Cluster headache and other trigeminal autonomic neuralgias' and 'Other primary headaches'. The recent classification offers an interesting opportunity to evaluate the clinical role and to discuss the mechanisms of some of the more relevant uncommon primary headaches.


RESULTS
Due to the low incidence of these uncommon headache forms, their diagnostic criteria, pathogenetic mechanisms and therapy are still debated. Differential diagnosis versus secondary headaches is also a crucial issue. In this review, some of the most important uncommon primary headaches are discussed in light of the most recent contributions to the literature.


CONCLUSIONS
The review focuses on the update of the main uncommon primary headaches, intending to clarify some controversial points and to indicate some headlines for further research.
Sandrini
Giorgio
G
University Center for Adaptive Disorders and Headache, IRCCS 'C. Mondino' Institute of Neurology Foundation, Pavia, Italy. gsandrin@unipv.it
Tassorelli
Cristina
C
Ghiotto
Natascia
N
Nappi
Giuseppe
G
D003937:Diagnosis, Differential; D051270:Headache Disorders, Primary / Q000145:classification* / Q000503:physiopathology* / Q000628:therapy; D006801:Humans