Headaches are extremely common. In fact, the World Health Organization (WHO) estimates that nearly half of adults the world over will have a headache at some point this year.

Headaches usually go away without causing further problems. Even many chronic headaches, such as migraines and cluster headaches, aren’t considered signs of more severe, underlying problems. They may need to be treated to improve your life, but they won’t put your life at risk.

Nevertheless, if you experience any unusual symptoms, make immediate arrangements to visit a doctor or the emergency room (ER).

The tension-type headache is the most common primary headache. It’s usually bilateral, which means that it affects both sides of the head. It’s commonly described as a squeezing sensation.

Tension-type headaches can be stress- or musculoskeletal-related. They can be treated with over-the-counter (OTC) pain medications such as ibuprofen (Advil, Motrin) and aspirin (Bayer).

These are common symptoms of migraine headaches. Migraines cause a throbbing sensation that usually occurs on just one side of the head.

They’re one of the top 10 causes of disability worldwide. They aren’t life-threatening, but they can severely impact your well-being.

If you’re experiencing migraines, it’s important for you to find out if there’s a cause. Migraines are most common in people 30 to 40 years old, according to The Migraine Trust. According to the Office on Women’s Health, around 75 percent of people affected by migraines are women.

Factors that can make a person more likely to experience chronic migraines include:

A variety of prescription drugs are available to treat migraines. Other treatments include OTC painkillers such as Excedrin Migraine and alternative methods such as acupuncture and herbal remedies.

Being woken by head pain is a common symptom of cluster headaches. These are also known as alarm clock headaches. Like migraines, cluster headaches occur most often on just one side of the head.

Cluster headaches happen in patterns called cluster periods, during which time the pain can be quite intense and prevent you from sleeping. Sometimes cluster headache pain is centered around one or both of the eyes.

Cluster headaches are generally not life-threatening. However, they can be debilitating, so you’ll want to find out the underlying cause.

Headaches that wake you from your sleep can also be caused by medical conditions such as high blood pressure, sleep apnea, and brain tumors. Depression and caffeine withdrawal can also cause cluster headaches.

Cluster headaches are most likely to affect people between 20 to 50 years old and men, according to the Mayo Clinic.

Home remedies that may bring relief include magnesium supplements, melatonin, and capsaicin cream. Other treatment methods include supplemental oxygen, triptan medications, and the intravenous medication dihydroergotamine (DHE).

A headache combined with a fever or a stiff neck may indicate encephalitis or meningitis. Encephalitis is inflammation of the brain, while meningitis is inflammation of the membrane that surrounds the brain.

When due to severe infection, either condition can be fatal. A compromised immune system, diabetes mellitus, and use of immune-system suppressing medication can make you more susceptible to these infections.

These infections must be treated immediately with intravenous antibiotic therapy.

A thunderclap headache is an extremely severe headache that comes on rapidly. It’s sometimes called a lone acute headache. It develops in 60 seconds or less and causes intense pain.

Thunderclap headaches can be caused by bleeding in the brain after an arterial aneurysm rupture, stroke, or other injury.

Pain from thunderclap headaches might occur anywhere on your head and extend to your neck or even areas of your lower back. The intense pain can last for an hour or more, and might be accompanied by dizziness, nausea, or loss of consciousness.

Meningitis, encephalitis, and brain tumors can cause thunderclap headaches. Hypertension is a more common cause.

The treatment for this kind of headache will depend on the cause. It’s important to speak to a doctor immediately if you have a headache that reaches peak intensity in a minute or less and doesn’t subside.

Any head trauma that causes a headache requires prompt medical attention. A headache after any kind of impact to the head can indicate a concussion.

Concussion is a particular risk if the headache continues to worsen after the injury. Even a minor fall or bump to the head can result in potentially life-threatening bleeding in the brain.

An ocular migraine can temporarily cause blindness or flashing lights in one eye. These symptoms will sometimes accompany a typical migraine headache as well.

If your migraines or regular headaches are accompanied by these visual disturbances, you need to tell your doctor. It’s possible that spasms in the retina cause these symptoms. People who experience ocular migraines may be more prone to long-term vision loss.

Migraines with auras, formerly known as classic migraines, can also cause “floating” lights or blind spots. In that case, however, the symptoms will occur in both eyes.

Besides the specific headache symptoms described above, any new or unusual headaches should be discussed with your doctor. Pay particular attention to headaches that:

Women who are experiencing menopause might find that they have new headache patterns or experience migraines when they never have before.

COPING WITH HEADACHESHeadaches are very common, but certain characteristics can signal a serious condition. For more common headaches, such as tension, cluster, or even migraine headaches, there are triggers, which can vary from person to person. Paying attention to your triggers and making small adjustments to your lifestyle may help avoid headache attacks. — Seunggu Han, MD

Sometimes a headache can indicate that your body is experiencing withdrawal from a chemical substance (such as caffeine). Other times your headache might be triggered by the dehydrating effects of alcohol consumption.

It’s also not unusual for people to experience headaches when they quit smoking tobacco products, due to nicotine withdrawal. These headache triggers are usually not indicative of any greater medical problem, and lifestyle choices can ensure that these headaches won’t continue.

Fatigue headaches, sometimes called exertional headaches, can be caused when your body is strained by too much physical activity. Eye muscle strain and lack of sleep can cause a dull throbbing headache that feels similar to an exertional headache.

Making sure to get enough rest, taking frequent breaks from computer work, and drinking the recommended amount of water each day will probably stop these headaches from happening.

KEEP A JOURNALKeeping a journal with details of what you were doing or what was happening at the time of your headaches may help to pinpoint things that you may want to avoid in the future to prevent a similar headache from recurring. — Stacy R. Sampson, DO

Treatments for headaches will vary widely, depending on their cause. Most headaches can be treated at home with ibuprofen or aspirin to relieve mild pain.

But if you’re experiencing any of the warning signs listed above, you’ll need to seek a doctor’s counsel for how to best treat your symptoms.

Antidepressant medication, blood pressure medication, lifestyle changes, and other treatment regimens may be recommended to aid you in getting headache relief.