Headache is a symptom associated with many illnesses. While head pain itself is the issue with primary headaches, secondary headaches are due to an underlying disease or injury that needs to be diagnosed and treated. Controlling the headache symptom will need to occur at the same time diagnostic tests are being considered. Some of the causes of secondary headache may be potentially life-threatening and deadly. Early diagnosis and treatment is essential, if damage is to be limited.
The International Headache Society lists eight categories of secondary headache. A few examples in each category are noted (this is not a complete list):
Head and neck trauma
* Injuries to the head may cause bleeding in the spaces between the layers of tissue that surround the brain (subdural, epidural and subarachnoid bleeding) or within the brain tissue itself.
* Concussions, where head injury occurs without bleeding
* A symptom of whiplash and neck injury
Blood vessel problems in the head and neck
* Stroke or transient ischemic attack (TIA)
* Arteriovenous malformations (AVM) may cause headache before they leak.
* The carotid artery in the neck can become inflamed and cause pain.
* Temporal arteritis (inflammation of the temporal artery)
Non-blood vessel problems of the brain
* Brain tumors, either primary, originating in the brain or metastatic from a cancer that began in another organ
* Seizures
* Idiopathic intracranial hypertension, once named pseudotumor cerebri, where there is too much cerebrospinal fluid pressure within the spinal canal.
Medications and drugs (including withdrawal from those drugs)
Infection
* Meningitis
* Encephalitis
* HIV/AIDS
* Systemic infections (for example, pneumonia or influenza)
Changes in the body's environment
* High blood pressure (hypertension)
* Dehydration
* Hypothyroidism
* Renal dialysis
Problems with the eyes, ears, nose throat, teeth and neck
Psychiatric disorders