Headache is pain in any region of the head. Headaches may occur on one or both sides of the head, be isolated to a certain location, radiate across the head from one point, or have a viselike quality. A headache may appear as a sharp pain, a throbbing sensation or a dull ache. Headaches can develop gradually or suddenly, and may last from less than an hour to several days.

Causes

Your headache symptoms can help your doctor determine its cause and the appropriate treatment. Most headaches aren't the result of a serious illness, but some may result from a life-threatening condition requiring emergency care. Headaches are generally classified by cause:

A primary headache is caused by overactivity of or problems with pain-sensitive structures in your head. A primary headache isn't a symptom of an underlying disease. Chemical activity in your brain, the nerves or blood vessels surrounding your skull, or the muscles of your head and neck (or some combination of these factors) can play a role in primary headaches. Some people may also carry genes that make them more likely to develop such headaches.

The most common primary headaches are:

Cluster headaches occur in cyclical patterns or cluster periods, are one of the most painful types of headache. A cluster headache commonly awakens you in the middle of the night with intense pain in or around one eye on one side of your head. Bouts of frequent attacks, known as cluster periods, can last from weeks to months, usually followed by remission periods when the headaches stop. During remission, no headaches occur for months and sometimes even years.Fortunately, cluster headache is rare and not life-threatening. Treatments can make cluster headache attacks shorter and less severe. In addition, medications can reduce the number of cluster headaches you have.

Migraine is a headache that can cause severe throbbing pain or a pulsing sensation, usually on one side of the head. It's often accompanied by nausea, vomiting, and extreme sensitivity to light and sound. Migraine attacks can last for hours to days, and the pain can be so severe that it interferes with your daily activities. For some people, a warning symptom known as an aura occurs before or with the headache. An aura can include visual disturbances, such as flashes of light or blind spots, or other disturbances, such as tingling on one side of the face or in an arm or leg and difficulty speaking.Medications can help prevent some migraines and make them less painful. The right medicines, combined with self-help remedies and lifestyle changes, might help.

Tension-type headache is generally a mild to moderate pain that's often described as feeling like a tight band around the head. A tension-type headache is the most common type of headache, yet its causes aren't well understood. Treatments for tension-type headaches are available. Managing a tension-type headache is often a balance between practicing healthy habits, finding effective non drug treatments and using medications appropriately.

Secondary headaches A secondary headache is a symptom of a disease that can activate the pain-sensitive nerves of the head. Any number of conditions — varying greatly in severity — may cause secondary headaches.

Possible causes of secondary headaches include:

Acute sinusitis causes the spaces inside your nose (sinuses) to become inflamed and swollen. This interferes with drainage and causes mucus to build up. With acute sinusitis, it might be difficult to breathe through your nose. The area around your eyes and face might feel swollen, and you might have throbbing facial pain or a headache. Acute sinusitis is mostly caused by the common cold. Unless a bacterial infection develops, most cases resolve within a week to 10 days. Home remedies may be all you need to treat acute sinusitis. Sinusitis that lasts more than 12 weeks despite medical treatment is called chronic sinusitis.

Brain aneurysm is a bulge or ballooning in a blood vessel in the brain. It often looks like a berry hanging on a stem.A brain aneurysm can leak or rupture, causing bleeding into the brain (hemorrhagic stroke). Most often a ruptured brain aneurysm occurs in the space between the brain and the thin tissues covering the brain. This type of hemorrhagic stroke is called a subarachnoid hemorrhage.A ruptured aneurysm quickly becomes life-threatening and requires prompt medical treatment.Most brain aneurysms, however, don't rupture, create health problems or cause symptoms. Such aneurysms are often detected during tests for other conditions.Treatment for an unruptured brain aneurysm may be appropriate in some cases and may prevent a rupture in the future. Talk with your caregiver to ensure you understand the best options for your specific needs.

High blood pressure (hypertension) is a common condition in which the long-term force of the blood against your artery walls is high enough that it may eventually cause health problems, such as heart disease. Blood pressure is determined both by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries. The more blood your heart pumps and the narrower your arteries, the higher your blood pressure. A blood pressure reading is given in millimetres of mercury (mm Hg). It has two numbers.