Headaches are one of the most common symptoms, taking a variety of forms and with dozens of possible causes. While most headache triggers aren't serious -- stress, a hangover, a cold, falling or bumping into something, the "brain freeze" from ice cream -- others can be more concerning.
People suffering headaches often fear one of two things, says Michael Sellman, chief of neurology at Mercy Medical Center in Baltimore: brain tumor or cerebral aneurysm (a blood vessel bleeding in the brain). But these are relatively rare. "Headache is not the most common presenting symptom of a brain tumor," Sellman says, while an aneurysm typically causes an abrupt "thunderbolt headache" that makes it impossible to do anything else and that warrants immediate medical attention.
More often, though, headaches come on gradually and reveal something going on beyond the head. "Headache can frequently be a barometer or early warning sign of something wrong elsewhere in the body," Sellman says.
Possible headache cause #1: Medication overuse
Why: Many people suffer unnecessarily from pain caused by medication mismanagement of earlier headaches. "They start taking pain medication -- over the counter or prescription -- for episodic headaches or a straightforward tension headache, but it turns into the headache that never goes away," says Deborah Friedman, professor of neurology and neurotherapeutics at the University of Texas Southwestern Medical Center.
The problem is that the wrong medication or dosage was used in the first place -- or was overused -- and the person becomes reliant on the drug. The whole pain system gets out of whack and it hurts to come off the pain reliever, yet it also hurts to take it.
What to notice: A chronic dull headache that never goes away or worsens without pain medication. At your next doctor's appointment, ask your doctor about a medication review. If you're caring for an older adult, ask your loved one's doctor whether it's time to reevaluate drugs that have been taken for years.
Some people also have adverse reactions to new medications or changed dosages, so if you suddenly begin to experience headaches, it's worth noting whether you've had a recent medication change.
Possible headache cause #2: Giant cell arteritis
Why: Giant cell arteritis (GCA) is an inflammatory disease of blood vessels that usually strikes older adults. The vessels most affected are in the scalp and head, which helps explain the presence of headaches.
What to notice: A new, persistent, throbbing headache in someone 60 to 65 is the typical first symptom. For many people, the pain is centered at the temples or near the eyes. It's usually accompanied by flu-like symptoms or weight loss. The person may also experience loss of energy, sweating, jaw pain and weakness, blurred vision, and enlarged lymph nodes.
Women are more often affected than men, according to the American College of Rheumatology. Seeing a doctor is important because when the condition goes untreated, the person with it is at increased risk for vision loss and small strokes.
Possible headache cause #3: COPD
Why: Chronic obstructive pulmonary disease (COPD) is the combination of emphysema and chronic obstructive bronchitis, usually caused by lung damage due to smoking. Headache is one of the less notorious yet fairly common symptoms of COPD, compared with shortness of breath and worsening cough. More than 30 percent of COPD patients (mean age of 63) were found to suffer headaches in a 2003 study in Turkey.
What to notice: COPD headaches are worst when you wake up in the morning. That's because you're not breathing deeply enough at night, causing carbon dioxide to build. This dilates blood vessels in the brain, causing headaches. Someone who's increasingly awakening with such headaches and who is a smoker or who may have been exposed to lung irritants should be checked for lung disease.
Possible headache cause #4: Dehydration
Why: The first symptoms of dehydration is usually thirst; headache, fatigue, and weakness can follow. Changes in blood flow and electrolyte balance are thought to contribute to dehydration headaches.
What to notice: The headache may worsen when you bend over, walk, or move in any way. Dehydration can affect people of any age, though older adults and those with dementia are especially vulnerable because they lose the ability to "read" the body's thirst signals. Caregivers may hear a complaint of headache (or notice the person rubbing the head) without realizing the underlying dehydration. Look for signs of dehydration in someone with dementia, including feeling warm to the touch, cracked lips, increased confusion, dark urine that may smell bad, and a fast pulse.
Extra fluids are always a good idea, especially in hot weather or if you can't be sure how much the person with headache is drinking.
How Referred Pain from Arthritis or a Pinched Nerve Can Cause Headaches
Why: When there's damage or injury to parts of the body that connect to the head via nerves, the pain can travel and be experienced as a headache. This "referred pain" can be from a toothache or earache, or from farther away -- a pinched nerve in the neck is an especially common headache cause, says Michael Sellman of the Mercy Medical Center. Sometimes the sufferer thinks of the headache and the body pain as two different problems, even though they're related.
What to notice: Degenerative changes in the neck that cause headache are especially common in older adults, says University of Texas's Deborah Friedman. Other causes include holding a phone crooked between your ear and shoulder or sitting in a round-shouldered, forward-hunching position.
If you find yourself reaching more and more often for pain meds, consider whether a good stretching regimen might be the real solution. If it's osteoarthritis, a doctor can recommend a safe pain-management strategy.
How Depression Can Cause Headaches
Why: "The cause of headaches is frequently psychological, including depression, anxiety, worry, and stress," neurologist Michael Sellman says. About 18 percent of people with migraines have major depression, according to the American Headache Society. Depression is considered a systemic (whole-body) disease.
What to notice: Continuous headache -- lasting for months or years -- and not responding to pain relievers is a red flag for depression, especially in subtle cases, according to Seymour Diamond, founder of Chicago's Diamond Headache Clinic. Familiarize yourself with the warning signs of depression, including changes in sleep or eating patterns and persistent sad or empty feelings.
Possible headache cause #7: Flu
Why: Flu (influenza) is an infection of the respiratory system -- including the lungs and throat. An out-of-the-blue headache can be a warning sign that you're about to get pretty sick.
What to notice: Fortunately, a headache caused by flu doesn't keep you in the dark for very long -- other symptoms (fever, achy muscles, fatigue, and weakness) tend to appear about the same time. Flu tends to strike more suddenly than a cold, although initial symptoms can be similar. (Both can cause a headache, for example.)
Pneumonia, which can develop from flu, also has headache as a hallmark symptom, along with chills, chest pain, nausea, and vomiting. If you're concerned about a flu or possible pneumonia, watch for the 10 Warning Signs That It's Time to Call a Doctor.
Possible headache cause #8: Meningitis
Why: Meningitis is an infection of the membrane surrounding the brain and spinal cord. Viral meningitis (caused by a virus) is the most common and milder form. Bacterial meningitis (caused by bacteria) is rarer but carries a higher risk of death. The infection causes inflammation that produces symptoms ranging from headache and fever to stroke.
What to notice: A severe headache is a common symptom of both forms of meningitis; because it's an infection, there's usually fever and flu-like symptoms as well, and sometimes a rash. Unlike the discomforts of flu or the common cold, a headache associated with meningitis is accompanied by a stiff neck. These symptoms can develop in a matter of hours or over a couple of days. People with weakened immune systems are at greater risk.
More about your headache
When a headache is bothering you, notice the details. Ask yourself a few key questions: