Headaches on the Left Side of the Head

Various headache types can produce pain on the left side of the head. Most of the time this pain isn’t a sign of something dangerous. However, if the pain is very severe or persists, a more serious issue could be responsible.

Headaches come in many forms, from tension headaches to migraines. There are also multiple reasons you might feel pressure or pain confined to the left side of your head.

Although headaches can affect one or both sides, having pain specifically on the left side is not diagnostic of any single condition.

Keep reading to find out potential causes and when you should contact your healthcare provider.

What leads to pain on the left side of the head?

Numerous triggers can lead to headaches. These include lifestyle choices like skipping meals as well as issues like medication overuse, and none are unique to left‑sided headaches.

Lifestyle triggers

If you get headaches often, altering your daily habits can significantly reduce symptoms. Common lifestyle-related triggers include:

• consuming alcohol
• missing meals
• heightened stress
• insufficient sleep

Additionally, processed foods that contain certain preservatives or artificial colors may provoke headaches in some individuals.

Medical triggers

• minor infections such as the common cold
• allergic reactions
• some prescription or over‑the‑counter drugs
• lack of fluids (dehydration)
• low iron (anemia)

Types of headaches that may affect just the left side

The following headache types can present on a single side of the head:

• Tension headaches: These often produce pain on both sides but aren’t usually indicative of a serious underlying illness.
• Migraine: Migraine is among the world’s most prevalent disorders and affects millions of people in the United States. Women are two to three times more likely to have migraines than men. For more on migraine relief techniques, see migraine head massage migraine relief.
• Cluster headaches: As implied by the name, cluster headaches occur in groups over days or weeks and are followed by remission periods—months or years without attacks.
• Sinus headaches: These headaches are linked to sinus infections (sinusitis) and the resulting inflammation. They are often mild to moderate but can occasionally be severe; such cases merit further medical evaluation.
• Chronic headaches: Any headache type—including migraine or tension—can be chronic if it occurs frequently over time.
• Cervicogenic headache: This headache originates from neck problems such as osteoarthritis, injury, or poor posture.
• Hemicrania continua: A continuous, often severe headache that remains on one side of the head, either left or right.
• SUNCT and SUNA: Short-lasting, unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and unilateral neuralgiform headache with autonomic symptoms (SUNA) always occur on one side. They are rare and not fully understood.
• Hypnic headaches: These develop during sleep and often wake the person up. About one in three sufferers experience severe pain.
• New daily persistent headache: NDPH starts suddenly and persists, frequently returning after the initial onset. It can be unilateral or bilateral.
• Post‑traumatic headaches: These can follow a head injury.

Potentially serious conditions

Some serious medical problems can produce a left‑sided headache. Examples include:

• dissection of the vertebral or carotid artery
• brain aneurysm
• temporal arteritis
• meningitis
• encephalitis
• brain tumor
• cerebrospinal fluid (CSF) leak

Are one‑sided headaches common?

Headaches that affect one side or both sides are common and often benign. Still, they can occasionally indicate a more serious issue. Seek medical attention or emergency care if you experience any of the following:

• the pain feels like the worst headache you’ve ever had
• a notable change in your headache pattern or intensity
• headaches that awaken you from sleep
• headaches that begin after a head injury
• confusion
• fever
• a stiff neck
• vision changes
• double vision
• pain that worsens with movement or when coughing
• numbness or weakness
• eye pain with redness
• loss of consciousness

Frequently asked questions

How can I get rid of a headache on the left side?

Treatment depends on the underlying reason. Sometimes drinking fluids, resting, or eating can ease a headache. If the pain is severe, long‑lasting, or does not respond to over‑the‑counter pain relievers, seek medical evaluation.

What does a one‑sided headache mean?

A headache may affect one side or both sides. Many common causes—dehydration, stress, migraine, and sinus congestion—can produce a unilateral headache. More serious causes include brain inflammation, severe infections, or tumors.

How does a dehydration headache feel?

A dehydration headache can resemble a tension headache, often described as a tightening band around the head, with pressure across the face and scalp. You might feel pressure on one or both sides and at the back of the head.

Dehydration can also trigger migraine. Migraine pain is typically intense, throbbing, usually on one side, and may be accompanied by nausea, vomiting, and sensitivity to light and sound.

What causes severe pain behind the left eye?

Severe pain behind the left eye can sometimes indicate serious conditions, such as a brain aneurysm, which need immediate medical care. Other causes include sinus pressure, migraine, or a cervicogenic headache.

Takeaway

Several headache types can produce pain confined to one side of the head. Most can be managed with over‑the-counter medicines and lifestyle adjustments like increased rest and hydration.

See your healthcare provider for severe headaches that disrupt your daily life. A doctor can identify the cause and suggest appropriate treatments to help control your pain.

Seek emergency care if you notice any neurological signs. Learn more about when a headache should prompt concern.