Headaches: Cluster - Introduction

Introduction

Most people have had headaches. There are many different kinds of headaches, and they range from being an infrequent annoyance to a persistent, severe, and disabling medical condition.

The brain is insensitive to pain, so that is not what hurts when you have a headache. Rather, the pain occurs in the following locations:

• The tissues covering the brain
• The attaching structures at the base of the brain
• Muscles and blood vessels around the scalp, face, and neck

Doctors categorize headaches as either primary or secondary. The category helps to distinguish the many different kinds of headaches and to determine right treatments for each.

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Primary Headaches

A headache is considered primary when it is not caused by a disease or other medical condition. Most primary headaches fall into three main types: tension-type, migraine, and cluster headaches.

• Tension headache is the most common primary headache and accounts for 90% of all headaches.
• Migraines are the second most frequently occurring primary headaches. Migraine is referred to as a neurovascular headache because it is most likely caused by an interaction between blood vessel and nerve abnormalities.
• Cluster headache is a less common type of primary headache. Although it is sometimes referred to as a neurovascular headache, evidence now suggests that its cause may lie in the hypothalamus, a region deep in the brain that regulates, among other functions, the biologic rhythms of the body.

Secondary Headaches

Secondary headaches are caused by other medical conditions, such as sinus infections, neck injuries, and strokes. About 2% of headaches are secondary to abnormalities or infections in the nasal or sinus passages, and they are commonly referred to as sinus headaches.

Chronic Daily Headaches

Chronic daily headaches are defined as any benign headache that occurs at least 15 days a month and is not associated with a serious neurologic abnormality. Most people with these headaches have them daily or almost daily and they can be quite debilitating.

Chronic daily headaches are subdivided into two categories:

• Short-duration headaches, or those lasting fewer than 4 hours. The most common short-acting chronic headaches are cluster headaches.
• Long-duration headaches, which last more than 4 hours. Tension-type headaches are the most common type of long-duration chronic (recurring) headaches and, in fact, the most common type of chronic headaches in general.

Click the icon to see an image of the different types of headache.

Review Date: 09/29/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org).