It is common for people to have a headache only on one side of the head sometimes. It could feel like a certain pressure or even pain only on either the left or right side of the head. Migraine to tension, there are many different reasons why a headache can happen, and some of these do manifest just on one just one side.

A headache on one side can often be resolved by taking over the counter medication or even home remedies. In fact, lifestyle changes and lots of rest can also make you feel better. However, if it doesn’t go away, it is important to get it checked. Health Shots got in touch with Internal medicine expert Dr Suchismitha Rajamanya, to understand we have a headache only on one side, and what it can mean.

Why are there headaches on one side of the head?

There are many reasons why one may experience headaches on one side of the head. Of the many types of headaches, tension headaches and migraines are prominent types. Other less common causes of headaches could be because of sinusitis, temporal arteritis, Trigeminal neuralgia and Cervicogenic headache. “However, it is important to also point out that not all the above-mentioned headaches result in pain on one side only. Headaches such as tension headaches are the most prevalent kind of headaches but can happen on one side or both sides of the head,” says Dr Rajamanya.

Migraine, on the other hand, can occur on one side of the head. A Sinusitis, specifically, can cause pain in the face and forehead, including one side of the head. This could be due to muscle tension where headaches often arise from muscle knots or imbalances on one side of the head or neck. A study published in National Institute of Health, supports this claim, adding that these headaches can be repetitive.

What causes headache on one side?

1. Lifestyle factors

Things you do every day can make your head hurt on one side. These habits don’t hurt your head directly but can bother nerves or blood flow, causing pain. “Stress, not drinking enough water, not sleeping well, sitting funny, certain foods or drinks, and taking too much pain medicine can all be causes. If you have headaches on one side, these things might be why. Changing them might help your head feel better. But it’s important to see a doctor if your headaches happen a lot or hurt a lot. They can tell you what’s going on and how to fix it,” says Dr Rajamanya.

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The connection between lifestyle and headaches on one side of the head is that certain habits or choices can indirectly irritate nerves or blood flow in a way that specifically affects that side of the head, leading to pain in that area. “For example, poor posture or muscle tension from stress can strain the muscles on one side of the neck and head, triggering headaches. Similarly, dehydration can affect the blood flow to the brain, causing aching sensations that might be felt more prominently on one side. Certain dietary triggers or medication overuse can also lead to headaches that manifest predominantly on one side,” says Dr Rajamanya. This study, published in Frontiers of Neurology, states that lifestyle and behavioural triggers can increase intensity of headaches.

2. Infections and allergies

Infections and allergies can cause headaches on one side of the head, though they can affect both sides as well. “Sinus infections, which occur when the sinuses become inflamed due to infection or allergies, can cause pain and pressure around the eyes and forehead, often felt more intensely on one side,” says Dr Rajamanya. Similarly, allergic reactions can lead to sinus inflammation and subsequent headaches, which may be localised to a side. In some cases, ear infections or dental problems can also cause referred pain to the head, which might be felt predominantly on one side. “The reason why the right side of the head might be affected specifically depends on factors such as the location of the infection or inflammation and individual variations in pain perception and nerve sensitivity,” explains Dr Rajamanya.

3. Medical conditions

Certain serious medical conditions can also cause headaches on one side. Vertebral or carotid artery dissection often manifests as a one-sided headache, states this study in Journal of International Medical Research. Another type of medical condition that causes headache on one side is brain aneursym. Encephalitis, or the inflammation of the brain tissue, also causes one sided-headache, according to this study, published in Journal of neuroimmunology. Brain tumours can also cause headaches.

4. Medications

There are certain medications or overuse of certain medications that can lead to pain on one side of the head. “One common example is the overuse of pain relievers such as ibuprofen, aspirin, or acetaminophen. When these medications are used excessively or inappropriately, they can lead to a condition called medication overuse headache or rebound headache,” says Dr Rajamanya. This type of headache typically occurs when the medication wears off and can cause pain primarily on one side of the head.

Additionally, certain medications, such as those used to treat high blood pressure or hormonal medications, may also list headaches as a potential side effect, which could manifest on either side of the head.

5. Neurological causes

Neurological causes of headaches on one side of the head can include conditions such as migraines, cluster headaches, and trigeminal neuralgia. “Migraines are neurological disorders characterised by severe throbbing pain, often on one side of the head, along with symptoms like nausea, vomiting, and sensitivity to light and sound,” says Dr Rajamanya. Cluster headaches are intense headaches that occur in clusters, causing severe pain usually around one eye or on one side of the head. A study, published in International Institute of Neurological Disorders and stroke, states that migraine headaches happen on one side as the pain is caused by the activation of nerve fibres inside the wall of brain blood vessels.

Trigeminal neuralgia is a condition that affects the trigeminal nerve, causing sudden, severe, stabbing pain in areas of the face, including the right side of the head. These neurological causes can lead to one-sided headaches due to their impact on nerve function and signalling in the brain.

6. Other medical causes

There are several medical conditions and consuming them can lead to pain on one side of the head. “These include temporal arteritis, involving inflammation of the temporal arteries; cervicogenic headaches arising from neck issues like arthritis or muscle tension; sinusitis causing pressure around the eyes and forehead; dental problems like tooth decay or TMJ disorders; head trauma leading to inflammation or nerve damage; and eye conditions such as glaucoma or optic neuritis,” says Dr Rajamanya. These conditions may result in localized pain on one side of the head due to various factors such as inflammation, nerve irritation, or referred pain patterns.

Different types of headaches

The various types of headaches are:

• Tension headaches: These are common and often feel like a band squeezing around your head.
•  Migraines: These are severe headaches often accompanied by nausea, vomiting, and sensitivity to light and sound.
•  Cluster headaches: These are intense headaches that come in groups, causing severe pain around one eye.
•  Sinus headaches: These happen due to sinusitis, causing pressure and pain in the forehead, cheeks, and around the eyes.
•  Rebound headaches: These occur when pain medications are overused and can lead to more headaches.
•  Cervicogenic headaches: These stem from issues in the neck, causing pain that spreads to the head.
•  Hormone headaches: These are linked to hormonal changes, like during menstruation or menopause.
•  Thunderclap headaches: These are sudden, severe headaches that can signal a medical emergency, like a brain bleed or stroke.
•  Exertional headaches: These happen during or after physical activity and can be due to strenuous exercise or other exertion.
•  Hypertension headaches: These occur due to high blood pressure and may be felt as a pulsating sensation in the head.

How to get rid of a headache on one side?

A one-sided headache, or even one that happens on both sides can be treated by rest, over the top medication as well as hydration. You can even try to grab a bite. Other things that can be tried include using a cold or warm compress, taking a nap, massaging your neck and shoulders gently, taking a warm bath. Yoga can also help. However, if the pain doesn’t go away in sometime, it is important to head to the doctor.