Different headache types can cause pain on the left side of the head. The pain usually isn’t cause for worry. But if the pain is intense or doesn’t go away, there may be a more serious cause.

There are many different kinds of headaches, from migraine to tension. There are also various reasons you might have pain or pressure only on the left side of your head.

That said, though headaches can affect one or both sides of the head, having a headache on the left side is not a trademark of any specific condition.

Keep reading to learn about the possible causes and when to call your doctor.

Many things can trigger headaches. They range from lifestyle factors like skipping meals to overusing medications, though none of them are specific to the headaches on the left side.

Lifestyle factors

If you experience frequent headaches, changing your lifestyle may greatly ease your symptoms. Any of these factors can trigger a headache:

  • drinking alcohol
  • skipping meals
  • being stressed
  • not getting enough sleep

In addition, eating processed foods containing certain food preservatives or artificial dyes may trigger headaches in some people.

Medical triggers

These are some types of headaches you might be experiencing on one side of the head:

  • Tension headaches: These can cause pain on both sides of the head, but they’re not usually a sign of an underlying condition.
  • Migraine: Migraine is one of the most common disorders in the world and affects about 1 in 6 people in the United States. Women are two to three times more likely to experience migraine attacks than men.
  • Cluster headaches: As the name suggests, cluster headaches arrive in clusters over days or weeks. These cluster attacks are followed by remissions — headache-free periods lasting for months or years.
  • Sinus headaches: These are severe headaches caused by an infection in the sinuses (sinusitis) and accompanying inflammation. They’re usually mild to moderate in intensity, but less often may be severe. In this case, the infection may be more serious and warrants extra examination by a doctor.
  • Chronic headaches: These can be any type — including migraine or tension headaches. They’re called chronic because they happen at least 15 days a month for 6 months or more.
  • Cervicogenic headache: This is when you experience a headache caused by a problem in your neck. It can be caused by different conditions such as osteoarthritis, an injury, or even inadequate posture.
  • Hemicrania continua: This is a severe headache affecting only one side of the head, either the left or the right.
  • SUNCT and SUNA: These are short-lasting, unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and unilateral neuralgiform headache with autonomic symptoms (SUNA). They are similar headache types and they always occur on one side of the head. These headaches are quite rare, with a prevalence of only 6.6 per 100,000. The cause is not fully understood.
  • Hypnic headaches: These headaches develop when you sleep, often causing you to wake up. 1 out of 3 people who get these headaches will experience severe pain.
  • New daily persistent headache: New daily persistent headache (NDPH) develops suddenly but reoccurs often after you get it the first time. It can affect one or both sides of the head.
  • Post-traumatic: A post-traumatic headache can occur after a head injury.

A few serious medical conditions can trigger a left-sided headache. These include:

Headaches on one or both sides of the head are common and usually don’t have a serious cause. But sometimes, they can signal a more serious problem. Call your doctor or get emergency help if:

  • the pain feels like the worst headache of your life
  • you’ve had a change in the pattern or severity of your headaches
  • the headaches wake you up at night
  • the headaches started after a blow to the head
  • confusion
  • fever
  • stiff neck
  • vision changes
  • double vision
  • pain that increases when you move or cough
  • numbness, weakness
  • pain and redness in your eye
  • loss of consciousness

How do I get rid of a headache on my left side?

How to treat a headache on the left side of your head can depend on the cause. Sometimes, drinking water, resting, or eating something can help relieve a headache. But if the pain is severe, long lasting, or doesn’t respond to over-the-counter (OTC) pain relievers, you may need medical attention.

What is a headache on one side of the head?

You can experience a headache on one side of the head or both sides of the head. Many conditions, such as dehydration, stress, migraine, and sinus congestion, can cause a headache on one side of the head. Serious causes can also include brain inflammation, severe infection, and brain cancer.

What does a dehydration headache feel like?

A headache caused by dehydration may feel like a tension headache. People may describe a tension headache as a band tightening around the head, squeezing the face and scalp. You may feel pressure on one or both sides and the back of your head.

Dehydration may also trigger migraine. A migraine episode can feel like an intense, throbbing pain, often on one side of the head that may occur with nausea, vomiting, and sound and light sensitivity.

What is a severe headache behind the left eye?

A severe headache behind the left eye may result from serious conditions, such as a brain aneurysm, that require emergency medical care. Other conditions, including sinus pressure, migraine, and a cervicogenic headache may also cause a headache behind one eye.

A few different types of headaches cause pain on only one side of your head. You can usually relieve these headaches with over-the-counter medications and lifestyle changes like more rest.

See your doctor for severe headaches that interfere with your life. Your doctor can discover what’s causing your headaches and recommend treatments to help manage your pain.

Get emergency medical attention if you experience any neurological symptoms. Learn how to know when to be concerned about a headache.