Cluster headaches are diagnosed on the basis of signs and symptoms. Many people report a delay of more than 5 years in the diagnosis of their cluster headaches.
Migraine-like symptoms (light and sound sensitivity, nausea, and vomiting) are major reasons for frequent misdiagnosis. In some cases, people are inappropriately treated for other types of headaches (like migraine) or health conditions (like sinusitis).
Signs and Symptoms
Cluster headache is diagnosed by the pattern of recurrent attacks, and by typical symptoms (pain on one side of head, swollen eyelid, watery eye, and runny nose).
Keeping a headache diary to record a description of attacks can help your health care provider make an accurate diagnosis. You should describe to your provider:
- Frequency of attacks (if keeping a diary, record the date and time of each attack)
- Description of pain (stabbing, throbbing)
- Location of pain
- Duration of pain
- Intensity of pain (using a number scale)
- Associated symptoms (tearing eyes, nausea and vomiting, and sweating)
- Any measures that bring relief (applying pressure, going out for fresh air)
- Any events that preceded or may have triggered the attack
- Any medications you are taking
- Behaviors during a headache (restlessness, agitation)
Medical History and Physical Examination
The provider will ask about your medical history and perform a physical exam that will include looking at your head, neck, and eyes. The provider may perform a neurologic examination, which includes a series of simple exercises to test strength, reflexes, coordination, and sensation.
In some cases, the provider may order an imaging test to check for brain abnormalities that may be causing the headaches. For imaging tests, magnetic resonance imaging (MRI) scans are preferred over computed tomography (CT) scans because MRIs do not expose people to radiation.
Ruling Out Other Headaches and Medical Conditions
As part of the diagnosis, the provider should rule out other headaches and disorders.
Migraines: Cluster headaches are often misdiagnosed as migraines but they are quite different based on:
- Frequency and Duration: Cluster headaches generally last 15 minutes to a few hours and can occur several times a day. A single migraine attack is continuous over the course of one or several days.
- Behavior: Cluster headache sufferers tend to move about while migraine sufferers usually want to lie down.
Nevertheless, both cluster headaches and migraine cause sensitivity to light and noise, which can make it difficult to distinguish between these two headaches.
Other Headaches: Other headaches that resemble cluster headaches include SUNCT (short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing) and paroxysmal hemicranias. Cluster headache may also resemble some secondary headaches notably trigeminal neuralgia, temporal arteritis, and sinus headaches. Cluster headache symptoms are usually precise enough to rule out these other types of headaches.
Tear in the Carotid Artery: A tear in the carotid artery (which carries blood to the brain) can cause pain that resembles a cluster headache. People with this condition may also respond to sumatriptan, a drug used to treat a cluster attack. An imaging test can identify this condition.
Orbital Myositis: An unusual condition called orbital myositis, which produces swelling of the muscles around the eye, may mimic symptoms of a cluster headache. This condition should be considered in people who have unusual symptoms such as protrusion of the eyeball, painful eye movements, or pain that does not dissipate within 3 hours.
Headache Symptoms that Could Indicate Serious Underlying Disorders
Headaches indicating a serious underlying problem, such as cerebrovascular disorder or malignant hypertension, are uncommon. (A headache without other neurological symptoms is not a common symptom of a brain tumor.) People with existing chronic headaches may, however, miss a more serious condition believing it to be one of their usual headaches.
You should contact your health care provider if the quality of a headache or accompanying symptoms has changed. Be sure to call your provider for any of the following symptoms:
- Sudden, severe headache that persists or increases in intensity over the following hours, sometimes accompanied by nausea, vomiting, or altered mental states (possible indication of hemorrhagic stroke, which is also called brain hemorrhage).
- Sudden, very severe headache, worse than any headache ever experienced (possible indication of brain hemorrhage or a ruptured aneurysm).
- Chronic or severe headaches that begin after age 50.
- Headaches accompanied by other symptoms, such as memory loss, confusion, loss of balance, changes in speech or vision, or loss of strength in or numbness or tingling in arms or legs (possibility of stroke).
- Headaches after head injury, especially if drowsiness or nausea are present (possibility of brain hemorrhage).
- Headaches accompanied by fever, stiff neck, nausea and vomiting (possibility of meningitis).
- Headaches that increase with coughing or straining (possibility of brain swelling).
- A throbbing pain around or behind the eyes or in the forehead accompanied by redness in the eye and perceptions of halos or rings around lights (possibility of acute glaucoma).
- A one-sided headache in the temple in elderly people; the artery in the temple is firm and knotty and has no pulse; scalp is tender (possibility of temporal arteritis, which can cause blindness or stroke if not treated).
- Sudden onset and then persistent, throbbing pain around the eye that may spread to the ear or neck and is unrelieved by pain medication (possibility of blood clot in one of the sinus veins of the brain).