A lumbar puncture is a procedure in which cerebral spinal fluid is removed from the spine with a needle. A lumbar puncture is necessary to look for infection or blood in the spinal fluid. A lumbar puncture can also evaluate the pressure in the spinal column, which can be useful for people with idiopathic intracranial hypertension (usually young, obese women who have increased intracranial pressure), or other causes of increased intracranial pressure. In most cases, a CT scan should be done first.

All people who present with red flags indicating a dangerous secondary headache should receive neuroimaging. The best form of neuroimaging for these headaches is controversial. Non-contrast computerized tomography (CT) scan is usually the first step in head imaging as it is readily available in Emergency Departments and hospitals and is cheaper than MRI. Non-contrast CT is best for identifying an acute head bleed. Magnetic Resonance Imaging (MRI) is best for brain tumors and problems in the posterior fossa, or back of the brain. MRI is more sensitive for identifying intracranial problems, however it can pick up brain abnormalities that are not relevant to the person's headaches.

The American College of Radiology recommends the following imaging tests for different specific situations:

Cluster headaches are often misdiagnosed, mismanaged, or undiagnosed for many years; they may be confused with migraine, "cluster-like" headache (or mimics), CH subtypes, other TACs ( trigeminal autonomic cephalalgias), or other types of primary or secondary headache syndrome. Cluster-like head pain may be diagnosed as secondary headache rather than cluster headache.

A detailed oral history aids practitioners in correct differential diagnosis, as there are no confirmatory tests for CH. A headache diary can be useful in tracking when and where pain occurs, how severe it is, and how long the pain lasts. A record of coping strategies used may help distinguish between headache type; data on frequency, severity and duration of headache attacks are a necessary tool for initial and correct differential diagnosis in headache conditions.

Correct diagnosis presents a challenge as the first CH attack may present where staff are not trained in the diagnosis of rare or complex chronic disease. Although experienced ER staff are sometimes trained to detect headache types, CH attacks themselves are not directly life-threatening, they are linked to an increased risk of suicide.

Individuals with CH typically experience diagnostic delay before correct diagnosis. People are often misdiagnosed due to reported neck, tooth, jaw, and sinus symptoms and may unnecessarily endure many years of referral to ear, nose and throat (ENT) specialists for investigation of sinuses; dentists for tooth assessment; chiropractors and manipulative therapists for treatment; or psychiatrists, psychologists and other medical disciplines before their headaches are correctly diagnosed. Under-recognition of CH by health care professionals is reflected in consistent findings in Europe and the United States that the average time to diagnosis is around seven years. Medical students receive little training in differential diagnoses and management of headaches.

Cluster headache may be misdiagnosed as migraine or sinusitis. Other types of headache are sometimes mistaken for, or may mimic closely, CH. Incorrect terms like "cluster migraine" confuse headache types, confound differential diagnosis and are often the cause of unnecessary diagnostic delay, ultimately delaying appropriate specialist treatment.

Headaches that may be confused with CH include:

- Chronic paroxysmal hemicrania (CPH) is a unilateral headache condition, without the male predominance usually seen in CH. Paroxysmal hemicrania may also be episodic but the episodes of pain seen in CPH are usually shorter than those seen with cluster headaches. CPH typically responds "absolutely" to treatment with the anti-inflammatory drug indomethacin where in most cases CH typically shows no positive indomethacin response, making "Indomethacin response" an important diagnostic tool for specialist practitioners seeking correct differential diagnosis between the conditions.

- Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) is a headache syndrome belonging to the group of TACs.

- Trigeminal neuralgia is a unilateral headache syndrome, or "cluster-like" headache.

Though outwardly similar to cluster headaches, chronic paroxysmal hemicrania is rather different, and the two headaches are not a subset of one or the other. Key differences include:

- Different gender distributions – CPH is more common in women than men, with opposite occurring with cluster headaches.

- CPH attacks occur more frequently, but are shorter.

- Individuals with CPH are far more responsive to indomethacin than individuals with cluster headaches.

- CPH attacks can be provoked by neck movement.

- In a study conducted by Sjaastad, heating a patient's body will cause the painful side of the forehead to sweat more in CPH patients, while there will be less sweating on that side for those suffering from cluster headaches.

Although the original Silberstein–Lipton criteria and the original description by Vanast make no suggestion for the exclusion of migrainous features in NDPH, the current ICHD criteria exclude patients with migrainous features. When migraine features are present, classification thus becomes problematic.

It has been reported that migraine symptoms may be present in over 50% of NDPH patients. The current criteria definition thus excludes more than half of patients with new onset of daily headache. This exclusion due to migrainous features could have adverse scientific, diagnostic, and treatment consequences.

One proposal for reclassification of the criteria is from a study conducted on retrospective analysis of the records of 1348 patients regularly treated at the headache clinic of the Department of Neurology of Santa Casa de São Paulo, Brazil, and would be the following subdivision: NDPH with migraine features and without migraine features that would allow the inclusion of all individuals present who has a daily and persistent headache from the beginning.

Another proposed reclassification of the criteria is from a study conducted as a retrospective chart review of patients seen at the Headache Center at Montefiore Medical Center in Bronx, New York, from September 2005 to April 2009. The revised criteria for NDPH definition does not exclude migraine features (NDPH-R), and three subdivisions were created and described based on prognosis: Persisting, remitting, and relapsing–remitting. Additionally, this revised criteria would not include parts C or D currently required by the ICHD diagnostic criteria for NDPH.

A ten-patient study conducted by Pareja et al. found that all patients diagnosed with CPH were responsive to indomethacin and were able to completely control their symptoms. Doses of the drug ranged from 25 mg per day to 150 mg per day with a median dose of 75 mg per 24-hour period.

Almost all cases of CPH respond positively and effectively to indometacin, but as much as 25 percent of patients discontinued use of the drug due to adverse side effects, namely complications in the gastrointestinal tract.

According to a case study by Milanlioglu et al., 100mg of lamotrigine, an antiepileptic drug, administered twice daily alleviated all painful symptoms. No side effects were noted after two months of treatment. Dosage of lamotrigine was decreased to 50mg a day after the first two months, and no symptoms or side-effects were recorded after a three-month followup.

Use of topiramate has also been found to be an effective treatment for CPH, but cluster headache medications have been found to have little effect.

The ICHD Diagnostic Criteria is:

1. Headache that, within 3 days of onset, fulfils criteria 2-4

2. Headache is present daily, and is unremitting, for > 3 months

3. At least two of the following pain characteristics:

1. bilateral location

2. pressing/tightening (non-pulsating) quality

3. mild or moderate intensity

4. not aggravated by routine physical activity such as walking or climbing

4. Both of the following:

1. no more than one of photophobia, phonophobia or mild nausea

2. neither moderate or severe nausea nor vomiting

5. Not attributed to another disorder

Notes:

1. Headache may be unremitting from the moment of onset or very rapidly build up to continuous and unremitting pain. Such onset or rapid development must be clearly recalled and unambiguously described by the patient. Otherwise it is coded as 2.3 Chronic tension-type headache.

2. History and physical and neurological examinations do not suggest any of the disorders listed in groups 5-12 (including 8.2 medication overuse headaches and its subforms), or history and/or physical and/or neurological examinations do suggest such disorder but it is ruled out by appropriate investigations, or such disorder is present but headache does not occur for the first time in close temporal relation to the disorder.

As of 2013 tension headaches affect about 1.6 billion people (20.8% of the population) and are more common in women than men (23% to 18% respectively). Despite its benign character, tension-type headache, especially in its chronic form, can impart significant disability on patients as well as burden on society at large.

Drinking water and avoiding dehydration helps in preventing tension headache. Using stress management and relaxing often makes headaches less likely. Drinking alcohol can make headaches more likely or severe. Good posture might prevent headaches if there is neck pain. People who have jaw clenching might develop headaches, and getting treatment from a dentist might prevent those headaches. Biofeedback techniques may also help.

The following diagnostic criteria are given for ophthalmodynia periodica:

1. Head pain occurring as a single stab or a series of stabs

2. Solely felt in the areas surrounding the eyes and temples

3. Pain lasting only a few seconds with irregular frequency

4. No additional symptoms

5. "Not attributed to another disorder"

Ophthalmodynia periodica does not have a confirmed cause, being a primary headache, but can be identified with other primary conditions. "As many as 40% of all individuals with ice pick headaches have also been diagnosed as suffering with some form of migraine headache."

Preventive treatments of migraines include medications, nutritional supplements, lifestyle alterations, and surgery. Prevention is recommended in those who have headaches more than two days a week, cannot tolerate the medications used to treat acute attacks, or those with severe attacks that are not easily controlled.

The goal is to reduce the frequency, painfulness, and/or duration of migraines, and to increase the effectiveness of abortive therapy. Another reason for prevention is to avoid medication overuse headache. This is a common problem and can result in chronic daily headache.

Long term prognosis in people with migraines is variable. Most people with migraines have periods of lost productivity due to their disease; however typically the condition is fairly benign and is not associated with an increased risk of death. There are four main patterns to the disease: symptoms can resolve completely, symptoms can continue but become gradually less with time, symptoms may continue at the same frequency and severity, or attacks may become worse and more frequent.

Migraines with aura appear to be a risk factor for ischemic stroke doubling the risk. Being a young adult, being female, using hormonal birth control, and smoking further increases this risk. There also appears to be an association with cervical artery dissection. Migraines without aura do not appear to be a factor. The relationship with heart problems is inconclusive with a single study supporting an association. Overall however migraines do not appear to increase the risk of death from stroke or heart disease. Preventative therapy of migraines in those with migraines with auras may prevent associated strokes. People with migraines, particularly women, may develop higher than average numbers of white matter brain lesions of unclear significance.

The most common chronic treatment method is the use of medicine. Many people try to seek pain relief from analgesic medicines (commonly termed pain killers), such as aspirin, acetaminophen, aspirin compounds, ibuprofen, and opioids. The long term use of opioids; however, appears to result in greater harm than benefit. Also, abortive medications can be used to "stop a headache once it has begun"; such drugs include ergotamine (Cafergot), triptans (Imitrex), and prednisone (Deltasone). However, medical professionals advise that abuse of analgesics and abortive medications can actually lead to an increase in headaches. The painkiller medicines help headaches temporarily, but as the "quick fix" wears off, headaches become more re-current and grow in intensity. These "rebound headaches" can actually make the body less responsive to preventive medication. The conditions keep worsening if one takes paracetamol, aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) for 15 days a month or more. Therefore, analgesic and abortive medications are often advised for headaches that are not chronic in nature.

A physician may recommend engaging in sexual activity less strenuously. Case series have found indomethacin and beta blockers to be successful in treating these headaches. Propranolol, Bellergal, and triptans have also been used with success. Anecdotal and indirect evidence suggests a trial of magnesium supplementation may improve symptoms (in subjects with known or suspected low Mg levels).

Chronic headache, or chronic daily headache (CDH), is classified as experiencing fifteen or more days with a headache per month. It is estimated that chronic headaches affect "4% to 5% of the general population". Chronic headaches consist of different sub-groups, primarily categorized as chronic tension-type headaches and chronic migraine headaches. The treatments for chronic headache are vast and varied. Medicinal and non-medicinal methods exist to help patients cope with chronic headache, because chronic headaches cannot be cured. Whether pharmacological or not, treatment plans are often created on an individual basis. Multiple sources recommend "multimodal treatment", which is a combination of medicinal and non-medicinal remedies. Some treatments are controversial and are still being tested for effectiveness. Suggested treatments for chronic headaches include medication, physical therapy, acupuncture, relaxation training, and biofeedback. In addition, dietary alteration and behavioral therapy or psychological therapy are other possible treatments for chronic headaches.

A vascular headache is an outdated term to describe certain types of headache which were thought to be related to blood vessel swelling and hyperemia as cause of pain.

There is no doubt that "some" headaches are caused by vascular effects. However, it is no longer a recognized term and not mentioned in the Headache classification of the International Headache society (IHS), although it is still used by some physicians and still mentioned in some medical classification systems. There are many types of vascular headaches. Other types of vascular headaches include headaches produced by fever, cluster headaches, and headaches from a rise in blood pressure (OSU Wexner Medical Center, 2012).

Headaches that were described as being vascular headaches include:

- Cluster headache

- Migraine

- Toxic headache

Hypnic headaches are benign primary headaches that affect the elderly, with the average age of onset being 63 ± 11 years. They are moderate, throbbing, bilateral or unilateral headaches that wake the sufferer from sleep once or multiple times a night. They typically begin a few hours after sleep begins and can last from 15–180 min. There is normally no nausea, photophobia, phonophobia or autonomic symptoms associated with the headache. They commonly occur at the same time every night possibly linking the headaches with circadian rhythm, but polysomnography has recently revealed that the onset of hypnic headaches may be associated with REM sleep.

Lithium carbonate 200–600 mg at bedtime is an effective treatment for most patients but for those that can not tolerate Lithium, Verapamil, indomethacin or methylsergilide may be tried. Two patients have also responded to flunarizine 5 mg. It has also been shown that 1–2 cups of coffee or 100–200 mg of caffeine before bed can prevent hypnic headaches.

For diagnosis of hypnic headache syndrome, headaches should occur at least 15 times per month for at least one month. Included in the differential diagnosis of a new onset nighttime headaches in the elderly is drug withdrawal, temporal arteritis, Sleep apnea, oxygen desaturated, Pheochromocytoma, intracranial causes, primary and secondary neoplasms, communicating hydrocephalus, subdural hematoma, vascular lesions, migraines, cluster headaches, chronic paroxysmal hemicrania and hypnic headache. All other causes must be ruled out before the diagnosis of hypnic headache can be made.

These headaches are estimated to appear in roughly 1% of the population. They can occur with sexual activity at any age. It is more common in men than women, with studies putting the gender ratio between 1.2:1 and 3:1.

To relieve pain, some doctors suggest pressing the tongue against the roof of the mouth to warm the area, tilting the head back for 20 seconds, or drinking something warmer than whatever caused the headache. Some people report relief from breathing in through the mouth and out through the nose, thus passing warm air through the nasal passages.

A cold-stimulus headache, also known as brain freeze, ice-cream headache, trigeminal headache or its given scientific name sphenopalatine ganglioneuralgia (meaning "pain of the "sphenopalatine ganglion""), is a form of brief pain or headache commonly associated with consumption (particularly quick consumption) of cold beverages or foods such as ice cream and ice pops. It is caused by having something cold touch the roof of the mouth, and is believed to result from a nerve response causing rapid constriction and swelling of blood vessels or a "referring" of pain from the roof of the mouth to the head. The rate of intake for cold foods has been studied as a contributing factor. An cold-stimulus headache is distinct from dentin hypersensitivity, a type of pain that can occur under similar circumstances.

Cats and other animals have been observed experiencing a similar reaction when presented with a similar stimulus.

The term "ice-cream headache" has been in use since at least January 31, 1937, contained in a journal entry by Rebecca Timbres published in the 1939 book "We Didn't Ask Utopia: A Quaker Family in Soviet Russia".

These headaches are treated by determining the cause of the headache and treating or removing this cause

External Compression Headache is caused by any type of headwear. This includes headwear that places pressure on the head — including tight hats, helmets, headbands, headphones and goggles. It is not known why some people are more sensitive than others to this type of pressure. External compression headaches can affect anyone who uses headwear. The headaches are more common among people who have migraines. It is believed to affect about four percent of the population. It is also referred to as "swim goggle headache".

These headaches can be brought on by such innocuous sources as wearing a halter top (presses against the neck), earplugs (presses against the jaw and inner ear), or wearing even a tiny hair clip (compresses the scalp). There is no known preventative treatment except to avoid the offending trigger. However, once symptoms arise and the trigger is removed, "Triptan"-type migraine treatment is effective.

Headaches due to environmental causes are usually diagnosed by taking an exposure history.