Headache on the left side may cause generalized aching or pain in a specific place, such as behind the left eye. It may feel throbbing, sharp, or piercing.

Most people will experience a headache at some point in their life. Some headaches are minor and resolve with home treatment, but some are more severe and need medical care.

If a headache occurs with blurred vision, nausea, or any other symptom that causes concern, seek medical attention. If a person has a sudden, severe headache and weakness on one side of the body or confusion, they need emergency care.

Several kinds of headaches can cause pain on the left side, including migraine and cluster headaches.

Generally, doctors classify headaches as “primary” or “secondary.” For a person with a primary headache, the pain is the main symptom. A secondary headache results from another health issue, such as:

  • a brain tumor
  • a stroke
  • an infection

The headaches that result can occur in any location, including the left side.

This article explores the symptoms, causes, and treatments for headaches on the left side. It also provides more information about when to see a doctor.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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Migraine can cause a moderate to severe headache on the left side. The condition affects 12% of people in the United States, including 17% of women and 6% of men.

A migraine headache may throb and be worse on one side. The pain may begin around the eye or temple and then spread across the head.

Some other symptoms of migraine include:

  • changes to vision
  • nausea and vomiting
  • dizziness
  • extreme sensitivity to sound, light, touch, or smell
  • numbness or a tingling sensation in the face or extremities

One rare type of migraine, called a hemiplegic migraine, can also cause weakness in the limbs and face on one side of the body.

A migraine episode typically lasts 4–72 hours. A person may need to lie down in a darkened room and rest until the symptoms pass.

Experts do not understand the exact causes, but genetic factors and environmental triggers appear to play a role.

Common triggers include:

  • stress, a factor in 80% of cases
  • hormonal changes, present in 65% of cases
  • certain foods, such as alcohol, cheese, and chocolate
  • sleeping too much or too little
  • bright lights or lights that flicker
  • odors, such as perfumes

Is there a link between migraine and COVID-19?

A cluster headache can cause severe pain on one side of the head, often around the eye. The pain can be very severe, and it may feel sharp, burning, or piercing.

About 0.4% of people in the U.S. experience cluster headaches. When they occur, the headaches tend to arise in several episodes for 4–12 weeks, then stop, possibly for several years. They often affect the same side each time.

Common features include:

  • pain behind one eye, one temple, or one side of the forehead
  • pain that starts at night, usually 1–2 hours after going to sleep
  • pain that peaks after 5–10 minutes
  • severe pain that lasts 30–60 minutes
  • less intense pain that may continue for up to 3 hours

Related symptoms may include:

  • a blocked or runny nose
  • a drooping eyelid
  • watering and redness in one eye
  • a flushed or sweaty face

The exact cause is unknown, but experts believe that it involves a part of the brain called the hypothalamus and the nerves and blood vessels of the trigeminal system, which affects the eyes and face.

Cluster headaches often happen at the same time each day. They may also be more common in the spring or fall, and people may confuse them with allergy headaches. They usually affect people ages 20–50 years, and 80% of them are males.

Learn more about cluster headaches.

This type of headache can result from an injury to the neck, such as whiplash or arthritis, or other changes in the vertebrae at the top of the spine.

It can cause:

  • moderate to severe pain that starts in the neck and spreads to the eyes and face on one side
  • a stiff neck and reduced range of motion
  • pain around the eyes, neck, shoulders, and arms
  • nausea
  • blurred vision
  • sensitivity to light and sound

Steroid injections and nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil), may help manage the pain. With treatment, cervicogenic headaches should resolve within 3 months, though they may recur.

The pain and other symptoms may be cyclical and flare up periodically, though the frequency varies from person to person.

Find out more about cervicogenic headaches.

An autoimmune attack in which the body responds as if its blood vessels were harmful substances can lead to vasculitis, a type of blood vessel inflammation.

A common type of vasculitis is giant cell arteritis, also called temporal arteritis. This affects blood vessels in the head. It usually occurs in people over 50 years of age.

Vasculitis can cause a headache that is similar to a “thunderclap headache.” The pain is severe, and there is often no clear cause. With a thunderclap headache, the pain is most intense within 1 minute and lasts for at least 5 minutes. With a similar headache caused by vasculitis, the pain may take a little longer to develop.

Other symptoms can include:

  • a sudden loss of vision
  • pain on one side of the head or behind the eye
  • pain when chewing

Anyone who experiences these symptoms should receive medical advice. Not treating vasculitis can result in permanent vision loss.

What is giant cell, or temporal, arteritis?

A brain aneurysm is a weak spot in a blood vessel in the brain. It does not usually cause symptoms unless it ruptures. In this case, a potentially life threatening hemorrhage can result.

A person may develop a thunderclap headache, which involves sudden, severe pain. They may feel as if they have been hit hard on the head, and they may also have weakness on one side of the body.

Other possible symptoms include:

Learn more about brain aneurysms.

If a person has a headache that is severe or persistent or if the pain occurs with any other symptoms, they should receive medical advice.

Additional symptoms include:

  • blurred vision
  • fever
  • sweating
  • nausea and vomiting
  • weakness on one side of the body

It is also important to consult a doctor if:

  • Headaches first develop after the age of 50.
  • There is a significant change in the pattern of headaches.
  • Headaches steadily get worse.
  • There are changes to the person’s mental function or personality.
  • Headaches occur after a blow to the head.
  • Headaches make daily life hard to manage.

Anyone with a severe, sudden headache should receive emergency care, as this may be a sign of a stroke or aneurysm.

Many people can treat a headache with over-the-counter (OTC) medication and rest.

When possible, the following measures may help prevent some types of headache:

  • avoiding or managing stress
  • having a regular sleep pattern
  • avoiding known triggers

A doctor may prescribe stronger pain relief medications for severe pain.

The following are some questions people frequently ask about headaches.

What is a stroke headache like?

A headache that may be due to a stroke is typically sudden, intense, and persistent. It may feel different from any other type of headache a person has experienced previously.

Does the location of a headache mean anything?

Generally, the location of a headache indicates the type of headache a person may be experiencing.

A headache on the left side may result from migraine, vasculitis, cluster headaches, or other types.

Often, a person can treat a headache at home with OTC remedies and rest. However, if headaches are severe, persistent, or otherwise concerning, contact a healthcare professional.

Anyone with a sudden, severe headache and weakness on one side of the body or confusion requires emergency care.

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