**2. Classification of headaches**

Although the concept of cephalea has mostly remained the same since it was first used to describe this type of disorder, its classification has been evolving continuously in line with modern physiopathological and pharmacologic concepts. The term cephalea or cephalalgia denotes pain located anywhere in the head and neck, regardless of the etiology; however, such a vast subject requires a very detailed classification scheme to determine which would be the best treatment for each type. Headaches are divided into two major groups: primary headaches and secondary headaches. Primary headaches are those appearing spontaneously with no association to any other disease or medical condition, while secondary headaches are those appearing in close temporal relation to another condition known to produce cephalea [7]. The main difference between both groups is whether or not an association is found with another cause, thus primary headaches have an intrinsic physiopathology while secondary cephalea is the consequence of another disease, trauma, or medical condition.

Primary cephalalgia is divided into four major categories:


While secondary cephalea has eight:


From the above-mentioned cephalea types, migraine and tension-type headaches represent up to 80% of all cases [10]; however, it is important to recognize all other types of cephalea so as to avoid misdiagnosis and treatment errors since these could be the first steps toward the overuse and abuse of headache treatment drugs.
