Knowing what causes headaches is critical because:
- Your headache could be a symptom of another condition, and that condition may be serious and even life-threatening.
- The more you know about the type of headache you have, the better you can treat the pain and even avoid the activities, foods, medications and environmental conditions that trigger your headaches.
The International Headache Society (IHS) recognizes three general classifications for headaches that can help you and your physician to identify both the type of headache and what causes headaches.
Primary headaches are those not caused by an underlying condition. The most common is the tension headache, followed by migraines and cluster headaches. Although there’s a lot that’s unknown about what causes primary headaches, there are some suspected triggers—some or all of which may apply to your condition.
Eliminating the triggers may help you reduce the frequency and severity of primary headaches. However, for anything more than an occasional, mild headache, it’s best to consult your physician and observe any patterns that might suggest the cause:
- Tension headaches may be triggered by conditions and activities that cause stress, emotional distress and muscle tension. Research is ongoing, but some of the possible causes may include: poor posture, prolonged sitting, jaw clenching, sleep apnea, anxiety, intense work, and even light sensitivity.1
- Cluster headaches, the rarest form of primary headaches, are most common in men in their late 20s. They’re called cluster headaches because they occur daily (usually around the same time) for periods of a week or longer, followed by long periods (months/years) without headaches. While their exact cause is unknown, the pattern suggests they may be tied to the body’s biological clock (located in the hypothalamus) and may be genetic. Researchers have not clearly identified triggers for cluster headaches.2
- While there’s still much to study and learn about migraine headaches, the cause may be some combination of genetics, chemical/hormonal imbalances, and environmental/activity factors. Also, researchers have identified some migraine triggers:
- Environmental changes—bright lights, loud noises, fumes and changes in weather or altitude
- Stress and anxiety—including depression and extreme fatigue
- Food sensitivities—specifically the chemicals commonly found in processed foods, aged cheeses, smoked fish and cured meat (food tenderizers, sodium nitrate, phenylalanine and tyramine)
- Activities—ranging from intense physical activity to being too sedentary
- Caffeine/Alcohol/Smoking—especially highly-caffeinated beverages and wine
These headaches typically are symptomatic of trauma, illness or a particular activity, such as drinking or smoking. Because what causes many secondary headaches may be life-threatening, it is important to consult your healthcare provider immediately to identify the cause. Some of the more common causes include:
- Sinus inflammation and pressure—A headache and facial pain are the most common symptoms due to the congestion and associated pressure of acute sinusitis. The most common causes are infections (viral, bacterial or fungal), allergies, dental infection, nasal polyps or environmental irritants (smoke, dust).
- Caffeine/Alcohol/Smoking—Headaches can be caused by caffeine withdrawal when you suddenly stop drinking caffeinated beverages. Excessive consumption of alcohol may result in hangover headaches. The nicotine in tobacco tends to stimulate blood vessels in the brain to narrow and bring on a headache.
- Concussion—A strong blow to the neck or head may lead to a mild brain injury or concussion that results in a post-traumatic headache (the primary symptom). Other associated symptoms may include nausea, dizziness, drowsiness and cognitive or emotional changes.
- Brain tumor—Both malignant and benign tumors that press on areas of the brain and cause swelling inside the skull that may trigger headaches ranging from a dull ache to throbbing, intense pain. Often these types of headaches become worse over time and include additional symptoms (e.g., numbness, double vision, nausea, seizures and cognitive problems).
- Stroke—Both ischemic stroke (blockage in the blood vessels) and hemorrhagic stroke (arterial bleeding in the brain) interrupt blood flow to the brain and can result in headaches. A stroke-related headache may feel similar to a tension headache but is usually associated with one or more of the following (all of which require immediate medical care):
- Severe pain and sudden onset.
- Weakness and/or numbness in face, arm, leg or one side of the body.
- Difficulty speaking, writing or understanding language.
- Vertigo or double vision.
- Cerebral aneurysm—When a weak spot in the wall of an artery in the brain fills with blood, it bulges out, puts pressure on nearby brain tissue or nerves and causes a severe headache. Cerebral aneurysms may be congenital or associated with some diseases, including polycystic kidney disease.
- Medication—Both medication overuse and sudden withdrawal may trigger a medication overuse headache (MOH), sometimes called a rebound headache. Although almost any medication can result in these headaches, pain relievers (analgesics), nonsteroidal anti-inflammatory drugs (NAISDs), sleep medications and narcotics are most common.
Cranial Neuralgias, Central and Primary Facial Pain and Other Headaches
Cranial or occipital neuralgia (nerve pain) headaches are the result of inflammation of one or more of the 12 cranial nerves. These are the nerves that control facial muscles and carry signals between the brain and head and neck. The pain may be acute, located behind the eye, result in scalp tenderness and sensitivity to light. Causes of cranial neuralgia can range from minor (neck tension) to severe (e.g., trauma, neck tumor, cervical disc disease, osteoarthritis, diabetes and gout).
Any headache that recurs frequently, produces moderate to severe pain, increases in severity and lasts more than a few hours is a reason to make an appointment with your primary healthcare provider. And in the most severe cases—such as after a trauma or when associated with other symptoms—emergency medical attention may be required.
If you are experiencing headaches that are out of the ordinary for you, you may want to speak with your doctor. Should you exhibit serious and sudden headache pain at any time—especially after any traumatic injury—seek help immediately!
2 Holland PR, Goadsby PJ.” Cluster headache, hypothalamus, and orexin.” Headache Rep. 2009;13(2):147-54. Accessed November 20, 2015.