Headache – Definition and Causes

Headache is defined as a pain or ache anywhere in the areas of head or neck. Headache can be a standalone condition or a symptom of another condition.

Headaches can be present in a single location, multiple locations, on both sides of head. Also, the presentation of headache can differ greatly. They can be throbbing, sharp, dull, rapid in onset or gradual, gripping, stabbing, radiating, last for hours to days.

Causes of headache

Headaches based on its causative factors can be classified into two categories:

Primary Headache

Primary headaches are the ones whose causative factor resides in the head itself. Although brain tissue itself has no pain receptors, the structures around it including blood vessels, nerves and muscles, both in head and neck can be responsible for pain. It is the pain related to these structures or chemical activity related pain head and neck that constitutes of primary headaches.

Common primary headaches are:

  • Migraine
  • Cluster headache
  • Trigeminal autonomic cephalalgia
  • Tension headache

Then, there are certain other causes of headaches which can be primary or a symptom of underlying disorder (hence secondary)

  • Chronic daily headaches
  • Headaches due to stimulus like alcohol, particular food types like processed meats, altered or lack of sleep, starvation, stress, posture related pain, temperature, external pressure.
  • Scalp/epicranial pain
  • Cough headaches
  • Sex headaches
  • Exercise headaches

Secondary headache

Secondary headaches are the ones which presents as a symptom of an underlying disorder that stimulates the pain-sensitive areas of head and neck. There are a number of conditions which may be responsible for secondary headaches. Some of them are:

  • Arterial tears
  • Acute sinusitis
  • Blood clots
  • Brain aneurysms
  • Brain freeze (eating cold food like ice creams)
  • Brain arterio-venous malformations i.e. blood vessels abnormal formation in brain
  • Chiari formation
  • Carbon monoxide poisoning
  • Concussion
  • Dental problems
  • Dehydration
  • Ear infection particularly middle ear
  • Glaucoma
  • Giant cell arteritis
  • Hangovers
  • Hypertension
  • Inflammation of brain tissues (encephalitis)
  • Influenza
  • Intracranial hematoma due to blood vessel rupture in brain
  • Meningitis
  • Monosodium glutamate
  • Rebound headaches after excessive use of pain killers
  • Panic attacks
  • Pressure from excessively tight headgear like goggles, turbans or helmets
  • Pseudotumor cerebri
  • Stroke
  • Spinal headaches
  • Toxoplasmosis
  • Thunderclap headaches

Suggested reading

1. Headache – definition and causes

2. Headache—Signs, symptoms and management

3. Treating headache with some simple home remedies

4. Headache–When to see a doctor