Headaches 101

Cluster Headaches and Secondary Headaches

The intense pain behind your eye? That's a cluster headache.
The intense pain behind your eye? That's a cluster headache.
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One of the most intense types of headaches is a cluster headache. The pain is usually localized to one side of the head, generally behind one­ eye, which often becomes bloodshot as it tears up and swells. Sometimes the drooping of one eyelid or a reddening eye can indicate the onset of an attack.

Cluster headaches get their name because they can come in repeated bursts, with each burst lasting 15 minutes to three hours. These bursts of pain can appear and disappear, all without warning, in a cycle that continues for days, weeks or months. Sometimes the headaches then stop abruptly for many months, only to start up again during the same season of the following year. Thankfully, only about one in a thousand people has to deal with the experience of cluster headaches.

Tension, migraine and cluster headaches are the three most common types of primary headaches, but countless others exist as well. In total, more than 150 types of headache are categorized by the International Headache Society. Here are a few examples:

  • Exertion or exercise headaches typically appear during or after physical activity, and are linked to the widening of blood vessels required to deliver increased amounts of oxygen to the muscles.
  • Mixed headaches come with symptoms of both tension and migraine headaches. To treat mixed headaches, a combination of tension and migraine treatments must be carefully balanced.
  • Ice cream headaches, also called "brain freeze," occurs when cold foods pressing on the roof of your mouth trigger overlying nerves to quickly widen blood vessels and increase blood flow -- possibly in an attempt to warm up the head as a response to the cold.
  • Migraine equivalents are perceived as pain coming from somewhere besides the head. The most common type is an abdominal migraine, which can result in abdominal pain and vomiting, but no head pain.
  • Hemiplegic migraine is a rare type of migraine that can cause temporary motor paralysis and sensory deficits on one side of the body, followed by a very severe headache.
  • Chronic daily headache (CDH) sufferers experience headaches more than 15 days per month. There are several different types of CDH, including chronic migraines, chronic tension headaches and chronic cluster headaches.

Secondary headaches, in contrast to primary headaches, arise from an underlying injury or illness. They're uncommon but often very serious. There are many possible causes of secondary headaches, including brain tumors, strokes and infections. A sinus infection is one example of a common cause for a secondary headache. In this case, swelling, increased pressure and inflammation in the sinus cavity causes severe, localized pain. Migraines are commonly misdiagnosed as sinus headaches due to similar symptoms. Secondary headaches can indicate the presence of a serious issue that requires immediate medical treatment.

If you experience headaches that are severe, recurring or accompanied by unusual symptoms, it's smart to consult your primary care physician. He or she might ask a series of questions about risk factors and family history, perform a physical exam and run relevant diagnostic tests. Based on the findings of the examination, the physician may recommend lifestyle changes, prescribe drugs or refer you to a headache specialist. Unfortunately, distinguishing between different types of headaches isn't always easy. For example, there aren't even definitive tests able to confirm or rule out the presence of many headache types.

OK, so we've briefly covered some of the major types of headaches, but what causes them? And why are they so painful?