skip to main content


Your complete online medical source

Navigate by theme:


Return to index


I'm very brave generally, only today I happen to have a headache.
Tweedledum in Alice in Wonderland

Headaches are one of the most common health complaints. Some possible causes include tension, infection, allergy, injury, hunger, changes in the flow of blood in the vessels of the head, or exposure to chemicals.

Most headaches that occur without other symptoms will respond well to self-care. The majority of headaches--more than 90 percent--are caused by tension and respond well to Prevention and Home Treatment.

An unusual headache that is very different from any you have had before, or a change in the usual pattern of your headaches, is a cause for concern. See "Headache Emergencies." However, if you have had similar headaches before and your doctor has recommended a treatment plan for them, emergency care may not be needed.

Headaches that routinely occur during or after physical exertion, sexual activity, coughing, or

sneezing may be a sign of a more serious disease and should be discussed with a health professional.

Headache Emergencies

Call your doctor now if you have:

  • A very sudden "thunderclap" headache.

  • A sudden, severe headache unlike any you have had before.

  • Headache with stiff neck, fever, nausea, vomiting, drowsiness, or confusion.

  • A sudden, severe headache with a stiff neck that develops soon after the headache starts.

  • Headache with weakness, paralysis, numbness, visual disturbances, slurred speech, confusion, or behaviour changes.

  • Headaches following a recent fall or blow to the head. See Head Injuries for information on head injuries.

Possible Headache Causes

If headache occurs:

Possible causes include:

On awakening.

Tension Headaches, See Tension Headaches; Allergies, See Allergies; Sinusitis, See Sinusitis; Neck Pain, See Neck Pain; TM Disorder, See Temporomandibular (TM) Disorder.

In jaw muscles or in both temples.

TM Disorder, See Temporomandibular (TM) Disorder; Tension Headaches, See Tension Headaches.

Each afternoon or evening; after hours of desk work; with sore neck and shoulders.

Tension Headaches, See Tension Headaches; Neck Pain, See Neck Pain.

On one side of the head, with visual disturbances or runny nose.

Migraine Headaches, See Migraine Headaches; Cluster Headaches, See Cluster Headaches.

After a blow to the head.

Head Injuries, See Head Injuries.

After exposure to chemicals (paint, varnish, insect spray, cigarette smoke).

Chemical headache. Get into fresh air. Drink water to flush poisons.

With fever, runny nose, or sore throat.

Flu, See Influenza (Flu); Sore Throat, See Sore Throat and Strep Throat; Colds, See Colds.

With fever, stiff neck, nausea, and vomiting.

Encephalitis and Meningitis, See Encephalitis and Meningitis.

With runny nose, watery eyes, and sneezing.

Allergies, See Allergies.

With fever and pain in the cheekbones or over the eyes.

Sinusitis, See Sinusitis.

On mornings when you drink less caffeine than usual.

Caffeine-withdrawal headache. Cut back slowly

Following a stressful event.

Tension Headaches, See Tension Headaches.

At the same time during the menstrual cycle.

Premenstrual Syndrome, See Premenstrual Syndrome.

With new medication.

Drug allergy. Contact your doctor.

With severe eye pain.

Possible acute glaucoma, See Cataracts and Glaucoma.

See a doctor now!

Top of Page