Causes

The causes of many chronic daily headaches aren't well-understood. True (primary) chronic daily headaches don't have an identifiable underlying cause.

Conditions that might cause nonprimary chronic daily headaches include:

• Inflammation or other problems with the blood vessels in and around the brain, including stroke
• Infections, such as meningitis
• Intracranial pressure that's either too high or too low
• Brain tumor
• Traumatic brain injury

Medication overuse headache

This type of headache usually develops in people who have an episodic headache disorder, usually migraine or tension type, and take too much pain medication. If you're taking pain medications — even over-the-counter — more than two days a week (or nine days a month), you're at risk of developing rebound headaches.