The many causes of headache. Migraine, vascular, drug-induced, and more.

Accurate diagnosis of headache can be challenging when the pain pattern and the source are not immediately recognized. The most common types of headache are primary (i.e., migraine, tension-type, and cluster). In addition, many secondary causes of head pain have been identified. Dr Levin reviews the major types of headache as categorized by the International Headache Society and provides a list of red flags that may signal a secondary headache.