Thinking about the the various types of headaches and headache sufferers it should not come as a surprise that the causes of headaches are just as diverse. There are many possible reasons for a headache including medical conditions like the fortunately rare instances of cerebral aneurysms and brain tumors. But the most common headaches also have generally common causes.

In all too many instances simple eyestrain such as that seen when staring for too long at a computer screen can lead to a headache. In other cases, a sinus infection resulting from a head cold or allergy can be the cause. Taking certain prescription medicines can also give you a headache.

Though the exact cause is not known in every instance, constriction of the blood vessels is also thought to be the culprit in a range of cases. Pain sensitive nerve fibers in the head line the walls of the blood vessels and when they contract the nerves send signals to the brain. Ironically, the brain itself cannot feel pain since it does not contain any pain sensitive nerve cells and tension-type or cluster headaches are the result.

But your blood vessels can dilate as well as contract and when they do so one theory at least holds that migraines and cluster headaches can result. Current research proposes that there are also other far more important factors at play when it comes to migraine headaches.

Tension headaches can arise from other sources like tension in the muscles of the neck, shoulder and even the jaw. People who have experienced TMJ disorder which is a condition caused by tension of the temporomandibular joint in which the jaw tightens against the skull are all too familiar with this.

In more serious cases headaches may be produced by an underlying disease and these are generally called 'secondary headaches'. The catalogue of diseases this can cause headaches is lengthy and will include everything from irritable bowel syndrome to scarlet fever.

Commonly environmental factors also play an important part. Carbon monoxide poisoning such as that resulting from the gas produced by many water heaters or a car exhaust can create severe headaches and indeed a headache is one of the prime symptoms of carbon monoxide poisoning. Other causes include allergies, lead poisoning and food poisoning.

Even where food is not itself toxic as will be the case where food is contaminated with a bacterial infection certain individuals will be sensitive to foods which will not affect people in general. Such common foods as chocolate and cheese can cause a headache in some individuals as will caffeine, some preservatives and red wine.

But posture, position and a number of other controllable factors can also be some of the most common causes. As more and more people are working with computers every day so we are seeing more eyestrain, jaw stress and neck tension.

About nine out of ten headaches are tension headaches that are normally the result of one or more of the factors detailed above. That means that in the overwhelming majority of cases the cure for your headache is simple and within your control.