A headache is a condition of mild to severe pain in the head; sometimes upper back or neck pain may also be interpreted as a headache.

Headaches have a wide variety of causes, ranging from eyestrain to inflammation of the sinus cavities to life-threatening conditions such as encephalitis, brain cancer, meningitis, and cerebral aneurysms. When the headache occurs in conjunction with a head injury the cause is usually quite evident; however, many causes of headaches are more elusive. The most common type of headache is a tension headache. Some people experience headaches when they are hungry or dehydrated.

It is common to take mild painkillers such as aspirin or acetaminophen (sold as Tylenol or Panadol) to relieve headaches.

Types of headache

• Tension headache
• Migraine
• Cluster headache
• Rebound headaches
• Ictal headache
• Ice cream headache
• Vascular headache