There are a number of different classification systems for headaches. The most well-recognized is that of the International Headache Society. Treatment of a headache depends on the underlying etiology or cause, but commonly involves analgesics. (pain reducers)

During a given year, 90% of people suffer from headaches. Of the ones seen in the ER, about 1% have a serious underlying problem.^[22]

Primary headaches account for more than 90% of all headache complaints, and of these, episodic tension-type headache is the most common.^[23]

It is estimated that women are three times more prone than men to suffer from migraines. Also, the prevalence of this particular type of headache seems to vary depending on the specific area of the world where one lives. However, migraines appear to be experienced by 12% to 18% of the population.^[23]

Cluster headaches are thought to affect less than 0.5% of the population, though their prevalence is hard to estimate because they are often mistaken for a sinusal problem. However, according to the existent data, cluster headaches are more likely to occur in men than women, given that the condition tends to affect 5 to 8 times more men.