Also called coin-shaped headache, nummular headache is characterized by small circumscribed areas of continuous pain on the head [1-3]. Nummular headaches are generally of mild to moderate intensity and confined to a round or elliptical unchanging area 2 to 6 cm in diameter.

The International Classification of Headache Disorders (ICHD) is an algorithmic system to define and classify all known headache disorders. It is divided into primary headache disorders such as migraine and symptomatic headaches which are a symptom of a different disorder.

According to diagnostic criteria established by the International Headache Society, patients must have had at least 5 headache attacks that lasted 4–72 hours (untreated or unsuccessfully treated) and the headache must have had at least 2 of the following characteristics: Unilateral location. Pulsating quality.

Tension-type headache typically causes pain that radiates in a band-like fashion bilaterally from the forehead to the occiput. Pain often radiates to the neck muscles and is described as tightness, pressure, or dull ache. Migraine-type features (unilateral, throbbing pain, nausea, photophobia) are not present.

Primary headache disorders

1. Migraine. This can include migraine with aura or without aura, and aura without headache.
2. Tension-type headaches. This type of headache includes episodic and frequent tension-type headaches.
3. Trigeminal autonomic cephalalgias.
4. Other primary headaches.

Description: Cluster headache attacks occurring in periods lasting from 7 days to one year, separated by pain-free periods lasting at least 3 months.

The headache is moderate to severe in intensity and can be intolerable in some sufferers. Movement, bright lights, and physical activity tend to aggravate the pain.

​​3 Types of Primary Headaches. ​Primary headaches include migraines, ​tension-type headaches, and cluster headaches. The Department of Neurology at National Neuroscience Institute (NNI) shares the symptoms of 3 primary headaches.

Headache Attributed to Infection Symptoms: Diffuse, moderate-to-severe pain caused by acute infection, accompanied by fever.

The International Classification of Headache Disorders (ICHD) is an algorithmic system to define and classify all known headache disorders. It is divided into primary headache disorders such as migraine and symptomatic headaches which are a symptom of a different disorder. The ICHD presents classification criteria,

For 2.3 Chronic tension-type headache, headache must, on at least 15 days, meet criteria B-D for 2.2 Frequent episodic tension-type headache; for 1.3 Chronic migraine headache must, on at least eight days, meet criteria B-D for 1.1 Migraine without aura.

The diagnostic difficulty most often encountered among the primary headache disorders is in discriminating between 2. Tension-type headache and mild forms of 1.1 Migraine without aura. This is more so because patients with frequent headaches often suffer from both disorders. Stricter diagnostic criteria have been suggested for 2.

It is divided into primary headache disorders such as migraine and symptomatic headaches which are a symptom of a different disorder. The ICHD presents classification criteria, comments and further information for headache disorders; it is revised from time to time and is now in its 3rd edition.