"Headache" is a general term that denotes pain in and around the skull, sometimes above or behind the eyes, and often including the upper cervical spine. Headaches vary dramatically in terms of intensity, frequency and type of pain, which can provide a clinician with clues as to the cause. Most headaches last less than 12 hours and resolve without intervention, as is the case with tension headaches. However, migraine headaches can last three days or more and require medication to continue with normal daily activities. Everyday, chronic headaches are unusual and should be considered as potentially serious until properly identified.
A serious but uncommon cause of everyday headaches is cancer of the brain or skull, as noted by the Mayo Clinic. Cancer can eat away bone, as is the case with Paget's disease of the skull, or it can grow large tumors in the brain, as is the case with glioblastomas. Pain from cancer can be excruciating or mild. Neurological problems that mimic a stroke should be noticeable if a brain tumor is large enough to generate daily headaches.
Infections and Other Conditions
Infections, such as brain abscesses and meningitis, are also serious but uncommon causes of everyday headaches. Infections usually produce severe pain. Conditions that increase intracranial pressure, such as high blood pressure, glaucoma and kidney disease, can generate headaches every day. Chronic sinus infections, although not considered life-threatening, can generate serious levels of pain and are a more likely cause of daily headaches, as cited in the book "Chronic Daily Headache."
Head trauma can generate chronic daily headaches, especially if a concussion results. Post concussion syndrome is usually a sign of a more serious head injury and can cause severe daily headaches and fatigue for months, according to Merck. Neurological damage from head trauma, which is very slow to heal, can cause severe headaches every day for many months or even years. Subarachnoid hemorrhages can produce short-term daily headaches, but usually lead to death if medical attention is not sought quickly.
Allergies and Toxicity
Food allergies and toxic reactions to chemicals often found in food are more common causes of daily headaches, according to "The Headache Book." Some common foods that can lead to everyday headaches include red wine, beer, dark chocolate, hot dogs, sandwich meats, cheese, food dyes and preservatives. Some toxic chemicals can cross from the blood into the brain and cause direct inflammation and headaches. Many cleaning products contain such chemicals. Merck adds that weekly pharmaceutical use can cause daily "rebound headaches," which is essentially a toxic reaction.
Posture and Lifestyle
Lifestyle risk factors that could promote frequent headaches include the following: Poor posture while working, daily exposure to fluorescent lighting, exposure to smoke or fumes, constant cell phone use, high stress situations, sleeping on your stomach, sleep deprivation, night shift schedules, heavy caffeine use, chronic dehydration, recreational drug use, and eye strain can all contribute to the possibility of daily headaches, as noted on the website Info-med.co.uk.