Headaches are a common cause of head pain. You can feel the pain from a headache on one or both sides of your head.
Headache pain comes on slowly or suddenly. It may feel sharp or dull and throbbing. Sometimes the pain radiates to your neck, teeth, or behind your eyes.
Pain from a headache usually subsides within a few hours and isn’t cause for worry. But intense pain in one side of the head or pain that doesn’t go away could be a sign of something more serious.
Keep reading to learn what causes headache pain on the left side of your head, and when to call your doctor.
Left side headache causes range from lifestyle factors like skipping meals to overusing medications.
All of these factors can trigger a headache:
Alcohol: Beer, wine, and other alcoholic drinks contain ethanol, a chemical that triggers headaches by widening blood vessels.
Stress: When you’re under stress, your body releases “fight or flight” chemicals. These chemicals tense your muscles and change blood flow, both of which cause headaches.
Foods: Certain foods are known to cause headaches, especially ones that contain preservatives. Common food triggers include aged cheeses, red wine, nuts, and processed meats like cold cuts, hot dogs, and bacon.
Lack of sleep: Insomnia can set off headaches. Once you have headaches, the pain can also make it harder to sleep at night. People with sleep disorders like obstructive sleep apnea are more likely to get headaches, in part because their sleep is disrupted.
Infections and allergies
Headaches are often a symptom of respiratory infections like a cold or the flu. Fever and blocked sinus passages can both set off headaches. Allergies trigger headaches via congestion in the sinuses, which causes pain and pressure behind the forehead and cheekbones.
Drugs that treat headaches can lead to more headaches if you use them more than two or three days a week. These headaches are known as medication overuse headaches, or rebound headaches. They occur almost every day, and the pain starts when you wake up in the morning.
Medicines that can cause overuse headaches include:
- acetaminophen (Tylenol)
- ibuprofen (Advil)
- naproxen (Naprosyn)
- aspirin, acetaminophen, and caffeine combined (Excedrin)
- triptans, such as sumatriptan (Imitrex) and zolmitriptan (Zomig)
- ergotamine derivatives, such as Cafergot
- prescription pain medications such as oxycodone (Oxycontin), tramadol (Ultram), and hydrocodone (Vicodin)
Nerve problems can sometimes be the source of head pain.
Occipital neuralgia: The occipital nerves run from the top of your spinal cord, up your neck, to the base of your skull. Irritation of these nerves can cause an intense, severe, stabbing pain in the back of your head or the base of your skull. The pain lasts from a few seconds to several minutes.
Giant cell arteritis: Also called temporal arteritis, this condition is caused by inflammation of blood vessels — including the temporal arteries along the side of the head. Symptoms can include headaches and pain in the jaw, shoulders, and hips, along with visual changes.
Trigeminal neuralgia: This condition affects the trigeminal nerve, which provides feeling to your face. It causes a severe and sudden jolt of shock-like pain in your face.
Pain on the left side may also result from:
- Tight headgear: Wearing a helmet or other protective headgear that’s too tight can put pressure on one or both sides of the head and cause pain.
- Concussion: A hard hit to the head can cause this type of traumatic brain injury. Concussions produce symptoms like headaches, confusion, nausea, and vomiting.
- Glaucoma: This rise in pressure inside the eye can lead to blindness. Along with eye pain and blurred vision, its symptoms can include a severe headache.
- High blood pressure: Normally, high blood pressure doesn’t cause symptoms. But in some people headaches can be a sign.
- Stroke: Blood clots can block blood vessels to the brain, cutting off blood flow and causing a stroke. Bleeding inside the brain can also cause a stroke. A sudden, severe headache is one warning sign of a stroke.
- Brain tumor: A tumor can cause an intense, sudden headache along with other symptoms such as vision loss, speech problems, confusion, trouble walking, and seizures.
There are many different kinds of headaches, from migraines to tension headaches. Knowing which one you have can help you get the right treatment. Here are a few of the most common.
Feels like: A band tightening around your head, squeezing your face and scalp. You can feel the pressure along both sides and the back of your head. Your shoulders and neck might also be sore.
Feels like: An intense, throbbing pain, often one side of the head. The pain is often accompanied by symptoms like nausea, vomiting, sound and light sensitivity, and auras.
Auras are changes in vision, speech, and other sensations. They occur before the migraine starts.
- flashes of light, shapes, spots, or lines in your field of vision
- numbness in your face or on one side of your body
- vision loss
- trouble speaking clearly
- hearing sounds or music that isn’t there
Cluster headaches are rare but intensely painful headaches. They get their name from their pattern. The headaches arrive in clusters over a period of days or weeks. These cluster attacks are followed by remissions — headache-free periods that can last for months or years.
Feels like: Intense pain on one side of your head. The eye on the affected side might be red and watery. Other symptoms include a stuffed or runny nose, sweating, and flushing of the face.
Chronic headaches can be any type — including migraine or tension headaches. They’re called chronic because they happen at least 15 days a month for six months or more.
Feels like: A dull throbbing pain, intense pain on one side of the head, or a vice-like squeezing, depending on which type of headaches you get.
See your doctor
Usually, headaches aren’t serious and you can often treat them yourself. 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 of your headaches.
- Headaches wake you up at night.
- The headache started after a blow to the head.
You should also see your doctor if you’re experiencing any of these symptoms alongside your headache:
- stiff neck
- vision loss
- double vision
- pain that increases when you move or cough
- numbness, weakness
- pain and redness in your eye
- loss of consciousness
Make an appointment to see your doctor if you have new headaches or your headaches have become more severe. Your doctor may send you to a headache specialist called a neurologist.
Your doctor will do a physical exam. You’ll be asked about your medical history and what symptoms you’re having.
They might ask you questions like these:
- When did the headaches start?
- What does the pain feel like?
- What other symptoms do you have?
- How often do you get headaches?
- What seems to trigger them?
- What makes the headaches better? What makes them worse?
- Is there a family history of headaches?
Your doctor may be able to diagnose your headache based on symptoms alone. But if they aren’t sure about what’s causing your headaches, they may recommend one of these imaging tests:
A CT scan uses a series of X-rays to create cross-sectional pictures of your brain. It can diagnose bleeding in your brain and certain other abnormalities.
A MRI uses powerful magnets and radio waves to create detailed pictures of your brain and its blood vessels. It provides a more detailed brain image than a CT scan. It can help diagnose strokes, bleeding in the brain, tumors, structural problems, and infections.
Here are a few things you can do at home to relieve headaches quickly:
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 relaxation and rest.
See your doctor for headaches that are severe or that interfere with your life. Your doctor can find out what’s causing your headaches and recommend treatments to help manage your pain.