Frequent headaches on left side of head

A: Headaches can come in many forms. Because the way you experience headaches can vary (and so do their underlying causes), you should make sure you’re paying close attention to how the headaches are affecting you.

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If you’re getting headaches only on one side of your head you shouldn’t worry, but you should make an appointment with your doctor. One-sided headaches can mean different things. But they often point to a group of disorders that will need a thorough exam to provide treatment.

According to headache specialist Emad Estemalik, MD, there are additional questions your doctor will focus on to identify what’s causing your one-sided headaches.

First, are the headaches continuous or do they come and go? And second, how long do the headaches last? Your answers help your doctor narrow down which category your headaches fall under.

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Categories of one-sided headache disorders

When we talk about unilateral or one-sided headaches, there’s a distinct family of headache disorders trigeminal autonomic cephalgias (or TACs). There are four distinct types of headaches:

1. Cluster headache — This type more often affects men. These headache attacks can occur around certain seasons. They last 15 to 180 minutes. They’re so severe and sharp that patients sometimes call them suicide headaches.
2. Hemicrania continua headache — This headache causes continuous pain on one side of the head for 24 hours while also causing sharp attacks of pain. A person will get a runny nose and may also have teary eyes.
3. Paroxysmal hemicrania headache — This one is similar to hemicrania continua, but people will get shorter attacks that last less than 24 hours, and they will be pain-free in between.
4. SUNCT and SUNA — These stand for short-lasting unilateral neuralgiform headache with donjunctival injection and tearing, and short-lasting unilateral neuralgiform headache with cranial autonomic symptoms. They are short-lasting headaches that rarely affect people. They cause a few seconds of severe head pain on one side of the head with teary eyes and runny nose.

“If you have one-sided headaches, it really is important to seek an evaluation by a neurologist or a headache specialist,” Dr. Est​emalik says. “A thorough exam is crucial for the proper treatment and brain imaging is often necessary to rule out any secondary causes.”

Left side headaches generally occur due to blows to the head and other mild injuries. They can also occur due to ear inflammations or migraines, and may be accompanied by other symptoms like local swelling, nausea or fever. 

Although it is not always a concerning finding, left-sided headaches that appear with symptoms like weakness on one side of the body, vision loss or seizures may be a sign of a more serious condition, like a brain tumor or serious brain injury. In these cases, imaging tests, like a CT or MRI, may be ordered. 

If the left side headache occurs frequently, you should consult your doctor for further assessment to rule out any serious conditions and to start treatment as necessary. 

Causes of left-sided headaches

The main causes of left side headaches include:

1. Wounds and injuries

A headache on the left side of the head can occur due to wounds and injuries that occur in the area. Generally, other symptoms do not emerge, other than some pain and mild swelling, which resolves within a few days. 

What to do: This type of headache tends to improve within a few days. However, if the pain is intense or persists for more than a week, you should see a doctor, who may recommend analgesics like acetaminophen. 

If you also experience symptoms like vomiting, seizures or loss of consciousness immediately after the injury, you should proceed to an emergency room for a more thorough assessment to rule out a serious brain injury. 

2. Migraine

A migraine can cause a left side headache. It is usually a throbbing pain that is accompanied by other symptoms like nausea, vomiting, and sensitivity to lights or noises. Learn more about migraine symptoms that can emerge. 

Generally, migraine pain worsens with physical activity, like walking or going up stairs. It can emerge with other symptoms like blurry vision and light flashes, which can occur before or during the headache. 

What to dor: If you experience a migraine, you should see a doctor or neurologist for evaluation and treatment as necessary. Treatment may involve medications, like analgesics and anticonvulsants, and lifestyle changes, like sleeping, ensuring adequate sleep routines and regular exercise. Read more about what can cause migraines and how they are treated. 

3. Ear infection 

An ear infection on the left side may cause a headache in this area. Other possible symptoms include fever and ear discharge. 

What to do: You are advised to consult a family doctor or ENT specialist if you suspect you have an ear infection. Treatment usually involves the use of medications like antibiotics and analgesics. Check-out other ways you can relieve ear pain at home. 

4. Tooth infection

When tooth infections occur on the left side of the mouth, pain can radiate to the areas around the affected teeth and to the head. 

Pain usually worsens when touching the affected tooth or with drinking hot or cold drink. Other common symptoms include swollen gums, easy bleeding and, in more severe cases, fever. 

What to do: If you think you may have a tooth infection, you should see your dentist for assessment and treatment as necessary. Depending on the severity, treatment may involve the use of antibiotics or even the extraction of the affected tooth. 

5. Temporal arteritis

Temporal arteritis is an inflammation of the blood vessels. When vessels on the left side of the head are affected, it can cause symptoms like a left side headache, transient vision loss and difficulty chewing. 

This pain tends to worsen with palpation, which can make common tasks like brushing you hair or sleeping on that side more difficulty. Other symptoms may include fever and general malaise. 

What to do: If you suspect you may have temporal arteritis, you should see a rheumatologist for assessment. If confirmed, treatment with medications (like oral corticosteroids) can be used to manage headache and prevent worsening. 

6. Tumors

Although they are rare, brain tumors can also cause left side headaches in some cases. Other symptoms will usually emerge, like seizures, weakness in certain areas of the body, nausea, vomiting  and episodes of temporary vision loss. 

The pain tends to be worse in the morning, and when lying down, coughing or with exerting force. 

What to do: If you suspect a brain tumor, you should see your doctor for thorough imaging tests, like CT and MRI. If confirmed, the headache will generally improve when the tumor is treated. Treatment may include surgery and chemotherapy. 

When to see the doctor 

You should consult a doctor if you experience any of the following: 

• Frequent headaches with no past history or obvious cause
• Weakness in a certain area of the body
• Seizures
• Fainting
• Vision loss, even if temporary 
• Double vision
• Cancer history 
• Headaches that worsen over time 
• Worsening of headache with lying down or coughing 
• Waking up at night from headaches 

In these cases, tests like MRIs or CTs may be ordered to rule out serious conditions, like brain tumors. Results will typically guide treatment, which will be determined by the doctor.