headache headache headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. it can occur as a migraine, tension-type headache, or cluster headache. there is an increased risk of depression in those with severe headaches. headacheother namescephalalgiaperson with a headachespecialtyneurologytypestension headache, cluster headache,sinusitis, cluster headache, migraine headache, hangover headache, cold-stimulus headache (brain freeze)treatmentover-the-counter painkillers, sleep, drinking water, eating food, head or neck massage headaches can occur as a result of many conditions. there are a number of different classification systems for headaches. the most well-recognized is that of the international headache society, which classifies it into more than 150 types of primary and secondary headaches. causes of headaches may include dehydration; fatigue; sleep deprivation; stress; the effects of medications (overuse) and recreational drugs, including withdrawal; viral infections; loud noises; head injury; rapid ingestion of a very cold food or beverage; and dental or sinus issues (such as sinusitis). treatment of a headache depends on the underlying cause, but commonly involves pain medication (especially in case of migraine or cluster headaches). a headache is one of the most commonly experienced of all physical discomforts. about half of adults have a headache in a given year. tension headaches are the most common, affecting about 1.6 billion people (21.8% of the population) followed by migraine headaches which affect about 848 million (11.7%). causes there are more than 200 types of headaches. some are harmless and some are life-threatening. the description of the headache and findings on neurological examination, determine whether additional tests are needed and what treatment is best. headaches are broadly classified as "primary" or "secondary". primary headaches are benign, recurrent headaches not caused by underlying disease or structural problems. for example, migraine is a type of primary headache. while primary headaches may cause significant daily pain and disability, they are not dangerous from a physiological point of view. secondary headaches are caused by an underlying disease, like an infection, head injury, vascular disorders, brain bleed, stomach irritation, or tumors. secondary headaches can be dangerous. certain "red flags" or warning signs indicate a secondary headache may be dangerous. primary ninety percent of all headaches are primary headaches. primary headaches usually first start when people are between 20 and 40 years old. the most common types of primary headaches are migraines and tension-type headaches. they have different characteristics. migraines typically present with pulsing head pain, nausea, photophobia (sensitivity to light) and phonophobia (sensitivity to sound). tension-type headaches usually present with non-pulsing "bandlike" pressure on both sides of the head, not accompanied by other symptoms. such kind of headaches maybe further classified into-episodic and chronic tension type headaches other very rare types of primary headaches include: cluster headaches: short episodes (15–180 minutes) of severe pain, usually around one eye, with autonomic symptoms (tearing, red eye, nasal congestion) which occur at the same time every day. cluster headaches can be treated with triptans and prevented with prednisone, ergotamine or lithium. trigeminal neuralgia or occipital neuralgia: shooting face pain hemicrania continua: continuous unilateral pain with episodes of severe pain. hemicrania continua can be relieved by the medication indomethacin. primary stabbing headache: recurrent episodes of stabbing "ice pick pain" or "jabs and jolts" for 1 second to several minutes without autonomic symptoms (tearing, red eye, nasal congestion). these headaches can be treated with indomethacin. primary cough headache: starts suddenly and lasts for several minutes after coughing, sneezing or straining (anything that may increase pressure in the head). serious causes (see secondary headaches red flag section) must be ruled out before a diagnosis of "benign" primary cough headache can be made. primary exertional headache: throbbing, pulsatile pain which starts during or after exercising, lasting for 5 minutes to 24 hours. the mechanism behind these headaches is unclear, possibly due to straining causing veins in the head to dilate, causing pain. these headaches can be prevented by not exercising too strenuously and can be treated with medications such as indomethacin. primary sex headache: dull, bilateral headache that starts during sexual activity and becomes much worse during orgasm. these headaches are thought to be due to lower pressure in the head during sex. it is important to realize that headaches that begin during orgasm may be due to a subarachnoid hemorrhage, so serious causes must be ruled out first. these headaches are treated by advising the person to stop sex if they develop a headache. medications such as propranolol and diltiazem can also be helpful. hypnic headache: a moderate-severe headache that starts a few hours after falling asleep and lasts 15–30 minutes. the headache may recur several times during the night. hypnic headaches are usually in older women. they may be treated with lithium. secondary headaches may be caused by problems elsewhere in the head or neck. some of these are not harmful, such as cervicogenic headache (pain arising from the neck muscles). the excessive use of painkillers can paradoxically cause worsening painkiller headaches. more serious causes of secondary headaches include the following: meningitis: inflammation of the meninges which presents with fever and meningismus, or stiff neck bleeding inside the brain (intracranial hemorrhage) subarachnoid hemorrhage (acute, severe headache, stiff neck without fever) ruptured aneurysm, arteriovenous malformation, intraparenchymal hemorrhage (headache only) brain tumor: dull headache, worse with exertion and change in position, accompanied by nausea and vomiting. often, the person will have nausea and vomiting for weeks before the headache starts. temporal arteritis: inflammatory disease of arteries common in the elderly (average age 70) with fever, headache, weight loss, jaw claudication, tender vessels by the temples, polymyalgia rheumatica acute closed-angle glaucoma (increased pressure in the eyeball): a headache that starts with eye pain, blurry vision, associated with nausea and vomiting. on physical exam, the person will have red eyes and a fixed, mid-dilated pupil. post-ictal headaches: headaches that happen after a convulsion or other type of seizure, as part of the period after the seizure (the post-ictal state) gastrointestinal disorders may cause headaches, including helicobacter pylori infection, celiac disease, non-celiac gluten sensitivity, irritable bowel syndrome, inflammatory bowel disease, gastroparesis, and hepatobiliary disorders. the treatment of the gastrointestinal disorders may lead to a remission or improvement of headaches. migraine headaches are also associated with cyclic vomiting syndrome (cvs). cvs is characterized by episodes of severe vomiting, and often occur alongside symptoms similar to those of migraine headaches (photophobia, abdominal pain, etc.). pathophysiology the brain itself is not sensitive to pain, because it lacks pain receptors. however, several areas of the head and neck do have pain receptors and can thus sense pain. these include the extracranial arteries, middle meningeal artery, large veins, venous sinuses, cranial and spinal nerves, head and neck muscles, the meninges, falx cerebri, parts of the brainstem, eyes, ears, teeth, and lining of the mouth. pial arteries, rather than pial veins are responsible for pain production. headaches often result from traction or irritation of the meninges and blood vessels. the pain receptors may be stimulated by head trauma or tumours and cause headaches. blood vessel spasms, dilated blood vessels, inflammation or infection of meninges and muscular tension can also stimulate pain receptors. once stimulated, a nociceptor sends a message up the length of the nerve fibre to the nerve cells in the brain, signalling that a part of the body hurts. primary headaches are more difficult to understand than secondary headaches. the exact mechanisms which cause migraines, tension headaches and cluster headaches are not known. there have been different hypotheses over time that attempt to explain what happens in the brain to cause these headaches. migraines are currently thought to be caused by dysfunction of the nerves in the brain. previously, migraines were thought to be caused by a primary problem with the blood vessels in the brain. this vascular theory, which was developed in the 20th century by wolff, suggested that the aura in migraines is caused by constriction of intracranial vessels (vessels inside the brain), and the headache itself is caused by rebound dilation of extracranial vessels (vessels just outside the brain). dilation of these extracranial blood vessels activates the pain receptors in the surrounding nerves, causing a headache. the vascular theory is no longer accepted. studies have shown migraine head pain is not accompanied by extracranial vasodilation, but rather only has some mild intracranial vasodilation. currently, most specialists think migraines are due to a primary problem with the nerves in the brain. auras are thought to be caused by a wave of increased activity of neurons in the cerebral cortex (a part of the brain) known as cortical spreading depression followed by a period of depressed activity. some people think headaches are caused by the activation of sensory nerves which release peptides or serotonin, causing inflammation in arteries, dura and meninges and also cause some vasodilation. triptans, medications that treat migraines, block serotonin receptors and constrict blood vessels. people who are more susceptible to experiencing migraines without headaches are those who have a family history of migraines, women, and women who are experiencing hormonal changes or are taking birth control pills or are prescribed hormone replacement therapy. tension headaches are thought to be caused by the activation of peripheral nerves in the head and neck muscles. cluster headaches involve overactivation of the trigeminal nerve and hypothalamus in the brain, but the exact cause is unknown. diagnosis differential diagnosis of headaches tension headache new daily persistent headache cluster headache migraine mild to moderate dull or aching painsevere painmoderate to severe pain duration of 30 minutes to several hours duration of at least four hours daily duration of 30 minutes to 3 hours duration of 4 hours to 3 days occur in periods of 15 days a month for three months may happen multiple times in a day for months periodic occurrence; several per month to several per year located as tightness or pressure across head located on one or both sides of the head located one side of head focused at eye or temple located on one or both sides of head consistent pain pain describable as sharp or stabbing pulsating or throbbing pain no nausea or vomiting nausea, perhaps with vomiting no aura no aura auras uncommonly, light sensitivity or noise sensitivity may be accompanied by running nose, tears, and drooping eyelid, often only on one side sensitivity to movement, light, and noise exacerbated by regular use of acetaminophen or nsaids may exist with tension headache most headaches can be diagnosed by the clinical history alone. if the symptoms described by the person sound dangerous, further testing with neuroimaging or lumbar puncture may be necessary. electroencephalography (eeg) is not useful for headache diagnosis. the first step to diagnosing a headache is to determine if the headache is old or new. a "new headache" can be a headache that has started recently, or a chronic headache that has changed character. for example, if a person has chronic weekly headaches with pressure on both sides of his head, and then develops a sudden severe throbbing headache on one side of his head, they have a new headache. red flags it can be challenging to differentiate between low-risk, benign headaches and high-risk, dangerous headaches since symptoms are often similar. headaches that are possibly dangerous require further lab tests and imaging to diagnose. the american college for emergency physicians published criteria for low-risk headaches. they are as follows: age younger than 30 years features typical of primary headache history of similar headache no abnormal findings on neurologic exam no concerning change in normal headache pattern no high-risk comorbid conditions (for example, hiv) no new concerning history or physical examination findings a number of characteristics make it more likely that the headache is due to potentially dangerous secondary causes which may be life-threatening or cause long-term damage. these "red flag" symptoms mean that a headache warrants further investigation with neuroimaging and lab tests. in general, people complaining of their "first" or "worst" headache warrant imaging and further workup. people with progressively worsening headache also warrant imaging, as they may have a mass or a bleed that is gradually growing, pressing on surrounding structures and causing worsening pain. people with neurological findings on exam, such as weakness, also need further workup. the american headache society recommends using "ssnoop", a mnemonic to remember the red flags for identifying a secondary headache: systemic symptoms (fever or