What Causes Headaches on One Side of the Head?

Headaches can affect different areas of the head and sometimes may occur on just one side. This pain may result from different types of headaches, such as migraines, cluster headaches, and cervicogenic headaches.

This article will explore the types of headaches that cause this kind of one-sided pain, as well as triggers, treatment options, and when to see a healthcare provider.

Left Side vs. Right Side Headaches

Headaches can sometimes only appear on one side of the head. This may happen on the left side or the right side of the head. It's poorly understood why the pain is sometimes isolated to one side of the head, but it's thought this may have something to do with vasculitis, which is inflammation of the blood vessels.

This one-side head pain may result from different types of headaches, including migraines, cluster headaches, and cervicogenic headaches.

Migraine

A migraine is a headache that typically causes a throbbing pain on one side of the head. It may occur on either the left or right side.

There are different forms of migraine. These include:

• Migraine with aura: This involves a person experiencing certain warning signs prior to the start of a migraine, like seeing flashing lights.
• Migraine without aura: This is the most common type of migraine. It usually happens without a warning sign.
• Migraine aura without headache: This is also referred to as a silent migraine and happens when an aura or other symptoms of a migraine occur, but the person doesn't get a headache.

Along with a throbbing pain on one side of the head, a migraine may be accompanied by other symptoms.

These may include:

• Sensitivity to light
• Sensitivity to sound
• Sensitivity to smell
• Sensitivity to touch
• Nausea
• Vomiting
• Vision changes, like an aura
• Numbness or tingling in the face, hands, or feet

Nausea due to migraine may worsen with activity, which can make migraines particularly disabling.

Some migraine symptoms can be located on the face, which may cause migraines to be mistaken for a sinus headache. Symptoms that occur in the neck may also be mistaken for a muscle spasm or arthritis.

It is possible for a migraine to be accompanied by sinus-like symptoms, including:

• Nasal congestion
• Pressure in the face
• Watery eyes

Most people who think they have a sinus headache do in fact have a migraine.

Cluster Headache

Cluster headaches are rare but severely painful headaches that are named for the pattern they follow. Those who experience cluster headaches may have a headache every day from four to 12 weeks. The headaches will happen in a "cluster" and often occur at the same time every day.

The pain from a cluster headache can be excruciating and commonly appears on one side of the head, behind the eye.

After the pattern of headaches stops, the headaches will go away. At this time, a period of remission begins. This is a time without any headache symptoms, which may last for months or even years before headaches return.

Headache clusters may happen at the same time of the year and are most common in the spring or autumn months.

Cluster headaches can present as a variety of symptoms. Typically, they will come on quickly.

Symptoms may include:

• A sharp, burning, or piercing feeling in one side of the head
• Severe pain
• Pain around the eye, temple, or one side of the face
• Red eyes
• Watery eyes
• Smaller pupil in one eye
• One eyelid that is drooping or swollen
• Blocked or runny nostril
• Sweat on the face
• Agitation
• Restlessness

A pain attack in a cluster headache can last from 15 minutes to three hours. The attacks may happen one to eight times every day and can happen daily for weeks or months.

For some people, the pain is so intense it will cause them to pace or rock to try and cope with the pain.

Cervicogenic Headache

A cervicogenic headache is a type of secondary headache, which means it is caused by a different issue in the body. Cervicogenic headaches are usually referred pain stemming from the neck.

Without treatment, the pain associated with a cervicogenic headache can be completely debilitating. Those who have a cervicogenic headache may experience:

• Worsening headache with the movement of the neck
• Worsening headache when pressure is applied to certain spots on the neck
• Reduced motion of the neck

Other symptoms may include:

• Pain on one side of the head
• Pain around the eye
• Pain in the neck
• Pain in the arms
• Pain in the shoulder
• Stiff neck
• Nausea
• Sensitivity to light
• Sensitivity to sound
• Blurred vision
  

Causes of Right- or Left Sided Headaches

Headaches can be due to a variety of causes, these can include environmental factors, genetics, stress and other factors.

Migraine

The exact cause of migraine is yet to be established. It is believed it may be due to abnormal activity in the brain that impacts nerve signals, blood vessels, and brain chemicals.

Genetics, a person’s genes and hereditary markers, may make some people more susceptible to migraines than others.

Migraines can be caused by a number of triggers. These include hormonal changes, stress or tension, shock, anxiety, depression, fatigue, poor sleep, low blood sugar, shift work, and jet lag.

Cluster Headaches

Like migraine, the cause of cluster headaches is unknown. It is believed to be associated with activity in the hypothalamus, an area of the brain that produces hormones that help control a variety of bodily functions.

It is also possible that genetics plays a role in the development of cluster headaches.

Those who smoke are at an increased risk of cluster headaches. Other possible triggers include:

• Alcohol
• Strong smells including paint, gasoline, or perfume

Cervicogenic Headache

A cervicogenic headache can result from such factors as:

• Whiplash (sudden force causing the head and neck to move backward and then forward)
• Fracture to the neck
• Arthritis in the neck
• Pinched nerve
• Slipped disk
• Sprained neck muscle
• Strained neck muscle
• Injury
• A fall
• Poor posture
  

Treatment

The treatment for headaches varies based on the type of headache and may include medication, physical therapy, or home remedies.

Migraine

Migraines can't be cured, but treatments can help reduce symptoms. Possible treatments for migraine include:

• Painkillers
• Triptans (medications to reverse some of the changes in the brain that trigger migraines)
• Anti-nausea medication
• Home treatments, like lying in a dark room

Cluster Headache

Over-the-counter (OTC) painkillers will not work for cluster headaches as they aren't fast-acting enough.

There are three treatments that can relieve pain if they are taken at the onset of a cluster headache. These include:

• Oxygen therapy (breathing pure oxygen via a face mask)
• Zembrace Symtouch (sumatriptan) injections
• Zomig (zolmitriptan) nasal spray (an alternative for those who don't like injections)

If used at the right time, these treatments can provide pain relief within 15–30 minutes.

Cervicogenic Headache

Treatment for cervicogenic headaches focused on targeting the cause of the pain, typically in the neck.

Possible treatments include:

• Medication
• Physical therapy
• Exercise
• Nerve blocks
  

When to See a Healthcare Provider

If you experience headaches that return or if your headache is not helped by painkillers, you should see a healthcare provider.

You should also see a doctor if:

• You have throbbing pain on the front or side of your head.
• You vomit.
• You feel nauseated.
• You find noise or light painful.
• You have pain in your jaw when you eat.
• You have blurred vision.
• You have double vision.
• Your scalp is sore.
• You have numbness in your arms or legs.
• You have weakness in your arms or legs.

You should call 911 or go to the emergency room if:

• Your headache came on suddenly and the pain is extreme.
• You have had a head injury.
• You have loss of vision.
• You feel confused.
• You have sudden difficulties with speech.
• You have sudden difficulties with memory.
• You have a high temperature.
• The whites of your eyes are red.
  

Summary

It is common for headaches to be isolated to the right or the left side of the head. Why headaches affect only one side of the head is poorly understood. These headaches may be classified as migraines, cluster headaches, or cervicogenic headaches.

If you are experiencing headaches, know that help is available. To start, you may consider making an appointment with a healthcare provider. A medical professional will be able to help identify what sort of headache you are experiencing, offer treatment options, and advise you on how to manage triggers.