What Are Cluster Headaches?

Cluster headaches are severely painful headaches that occur in clusters. You experience cycles of headache attacks, followed by headache-free periods.

The frequency of your headaches during these cycles may range from one headache every other day to several headaches per day. Pain from cluster headaches can be extremely severe.

Cluster headaches are most common between adolescence and middle age, but can occur at any age.

Older studies showed that cluster headaches were more commonly reported by men than women, such as a 1998 study published in Cephalagia, which shows that before 1960, men reported cluster headaches six times more often than women. Over time however, that gap has shrunk, and by the 1990s, cluster headaches were found in only twice as many men than women.

There are two types of cluster headaches: episodic and chronic.

Episodic cluster headaches occur regularly between one week and one year, followed by a headache-free period of one month or more.

Chronic cluster headaches occur regularly for longer than one year, followed by a headache-free period that lasts for less than one month.

A person who has episodic cluster headaches may develop chronic cluster headaches, and vice versa.

Cluster headaches usually start suddenly. A small percentage of people experience aura-like visual disturbances, such as flashes of light, before headaches begin.

Most commonly, headaches begin a few hours after you fall asleep and are often painful enough to wake you, but they may also begin when you are awake.

Headache pain becomes severe 5-10 minutes after the headache starts. Each headache usually lasts for several hours, with the most intense pain lasting between 30 minutes and 2 hours.

Cluster headache pain occurs on one side of the head, but can switch sides in some people, and is generally located behind or around the eye. It is described as a constant and deep burning or piercing pain. People with this pain say it is like a hot poker being stuck into your eye. The pain may spread to the forehead, temples, teeth, nose, neck, or shoulders on the same side.

Other signs and symptoms may be evident on the painful side of the head, including:

  • a droopy eyelid
  • a constricted pupil
  • excessive tearing from your eye
  • eye redness
  • sensitivity to light
  • swelling under or around one or both of your eyes
  • a runny nose or stuffy nose
  • facial redness or flushing
  • nausea
  • agitation or restlessness

The pain from cluster headaches is caused by the dilation, or widening, of the blood vessels that supply blood to your brain and face. This dilation applies pressure to the trigeminal nerve, which transmits sensations from the face to the brain. It is unknown why this dilation occurs.

Researchers believe that abnormalities in the hypothalamus, a small area of the brain that regulates body temperature, blood pressure, sleep, and the release of hormones, may be responsible for cluster headaches.

Cluster headaches may also be caused by a sudden release of the chemicals histamine, which fight allergens, or serotonin, which regulates mood.

Your doctor will ask you questions about your symptoms and give you a physical and neurological exam. This may include an MRI or CT scan of your brain to rule out other causes of the headaches, such as a brain tumor.

Treatment involves relieving and preventing your headache symptoms using medication. In rare cases, when pain relief and preventive treatment do not work, your doctor may recommend surgery.

Pain Medication

Pain medication relieves your headache pain once it has begun. Treatments include:

  • Oxygen: Breathing 100-percent pure oxygen when the headache begins can help relieve symptoms.
  • Triptan medications: A nasal spray medication called sumatriptan (Imitrex), or other tripitan medications constrict blood vessels, which can help ease your headache.
  • DHE: An injected medication called dihydroergotamine (DHE), can often relieve cluster headache pain within five minutes of use. Note: DHE can’t be taken with sumatriptan.
  • Capsaicin cream: Topical capsaicin cream can be applied to the painful area.

Preventive Medication

Preventive medications stop headaches before they start. These medications may not be 100-percent effective, but they can reduce the frequency of your headaches. These medications include:

  • blood pressure medications, such as propranolol (Inderal) or verapamil (Calan, Covera, Isoptin, Verelan), which relax your blood vessels
  • steroid medications, such as prednisone, which reduce nerve inflammation
  • a medication called ergotamine that keeps your blood vessels from dilating
  • antidepressant medications
  • anti-seizure medications, such as topiramate (Topamax) and valproic acid
  • lithium carbonate
  • muscle relaxants, such as baclofen


As a last resort, a surgical procedure can be used to disable the trigeminal nerve. The surgery can cause permanent pain relief for some patients, but serious side effects, such as permanent facial numbness, can result.

You may be able to prevent cluster headaches by avoiding the following:

  • alcohol
  • tobacco
  • cocaine
  • high altitudes
  • strenuous activities
  • hot weather
  • hot baths
  • foods that contain large amounts of nitrates, such as:
    • bacon
    • hot dogs
    • preserved meats

Cluster headaches are not life-threatening, but there is no cure for them. With these tips and treatments, your headaches may become less frequent and less painful over time, or they may eventually disappear completely.