While headache is a commonly reported flu symptom, migraine is not. However, a viral infection like the flu can trigger or worsen an existing migraine or headache disorder.

Primary headaches are when the headache itself is the health condition. This includes migraine, tension, and cluster headaches. Secondary headaches are symptoms of another health condition, such as an infection or injury.

Stress, nasal congestion, and dehydration can all contribute to a secondary headache when you have the flu.

We’ll explore:

  • the difference between headaches and migraine
  • why migraine episodes may occur if you have the flu
  • what treatments are available

Having a viral infection like the flu or COVID-19 puts a lot of stress on your body. The following factors could contribute to a secondary headache during flu illness or serve as a trigger for a primary headache, including migraine.

Blocked sinus cavities

The flu and common cold are both frequent culprits behind nasal congestion and sinus infections (sinusitis).

When you’re congested due to an illness or allergies, pressure builds up in your sinuses, the hollow cavities around your nose and eyes. If the membranes of your sinuses swell due to infection or inflammation, this can cause pain in your face and head.

It’s very common to feel a headache due to temporary congestion and no sinus infection.

“Sinus headache” is a common misdiagnosis of migraine. Most of the time, sinus headaches are not due to a sinus infection but are actually migraine or tension headaches. This is because migraine episodes can cause nasal symptoms as well, including runny nose, congestion, and pressure in the face.

Dehydration

Your body needs water to function, and this is especially true when you’re sick. As your immune system works to clear out an infection, you’re losing more water than you typically would. If you don’t sufficiently replace this water, you become dehydrated.

Fever and diarrhea — common flu symptoms — are two frequent contributors to dehydration.

There’s not much research on the connection between dehydration and headache, but it’s a widely recognized phenomenon. A 2021 study noted that dehydration headaches often resolved shortly after the person consumed fluids. The authors explained that dehydration seems to trigger or worsen underlying headache disorders.

Drinking plain water regularly can help prevent dehydration headaches, both flu-related and otherwise. Guidelines for how much water to drink a day depend on many individual factors.

Learn more about the importance of staying hydrated.

Increase of cytokines

Cytokines are molecules released by the immune system to help with injury and infection. Cytokines stimulate your body’s inflammatory response, telling it to go handle the flu or repair that muscle tear.

The body’s release of too many cytokines is called a cytokine storm or can indicate cytokine release syndrome (CRS). Too many cytokines in your system can lead to excess inflammation and pain.

Research into the connection between cytokines and migraine is ongoing. But experts believe that many migraine attacks are caused by an irregular inflammatory response located in your own immune system. As “mediators of the inflammatory pathway,” cytokines likely play a role in migraine episodes.

Stress

When you’re sick, your body is under a lot of physical stress as its immune system tries to expel an infection. Being sick causes emotional stressors too, such as worrying about falling behind at school, or missing friends.

The most common type of primary headache is a tension-type headache (TTH) or “stress headache.” Stress is a contributing cause of TTH, which usually resolves once the stressor has passed.

Stress is considered the most common trigger of migraine attacks. It’s also considered a significant factor in the frequency of migraine and tension headaches.

Getting help

Living with chronic pain can be exhausting.

In addition to medical care for your physical migraine symptoms, you deserve emotional and psychological support. Consider finding a therapist to help you cope and to provide a safe space to work through your emotions.

Here are some tips:

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Influenza (flu) is a viral infection that usually causes epidemics of infection every winter (flu season) in the United States. The contagious virus (influenza) is transmitted when a person who has contracted it talks or sneezes, releasing viral droplets into the air.

In addition to headaches, common symptoms of the flu include:

Most people who develop the flu recover in 2 weeks or less. However, complications like pneumonia, or ear and sinus infections can occur.

Doctors often suggest that people who experience migraine episodes keep a journal or log of their activities to help identify possible triggers. Noting the food you ate, or what the weather was like, prior to the pain can help identify triggers and avoid them next time.

In addition to stress, dehydration, and illness, some of the top triggers of migraine attacks include:

Read more about common migraine triggers.

Both migraine and headaches cause head pain that can derail your day, but how can you tell the difference between the two?

Migraine is considered a neurological disorder. A severe primary headache is only one symptom of it.

Migraine episodes are often one-sided and cause intense, throbbing pain. This pain can be enough to impair your ability to function and is usually considered more severe than that of tension or cluster headaches.

Migraine attacks tend to return repeatedly, usually after particular triggers like stress or eating a particular food. One of the distinguishing factors of migraine is that other symptoms usually accompany head pain.

These include:

Migraine attacks can also cause nasal symptoms, including clear discharge and congestion.

Learn more about episodic and chronic migraine episodes.

If you’re experiencing a secondary headache as a symptom of the flu, treating the infection should improve or resolve it. If your headache is the cause of a migraine episode, it may not resolve even if your flu symptoms do.

In this case, you need to address and treat your migraine attack on top of treating the flu.

Flu treatment

Treatment of the flu mostly involves:

If the flu leads to complications like a sinus infection or pneumonia, other treatments (including antibiotics, supplemental oxygen) may be necessary.

The most effective prevention against the seasonal flu is a yearly flu shot. Vaccination against the flu has been proven to lower your risk of contracting the virus and developing the flu, and lower your risk of being hospitalized or dying of the flu.

Find a location to get the flu vaccine near you.

Flu vaccines can cause temporary side effects, including soreness at the injection site, fatigue, and a low-grade headache.

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Migraine treatment

Migraine treatment centers on identifying your migraine triggers and avoiding them whenever possible.

Anti-CGRP tablets and injections are the latest and most promising treatment available for acute migraine attacks. These are also called CGRP antagonists or inhibitors. These medications work to reduce a protein that causes inflammation in your brain, calcitonin gene-related peptide (CGRP).

Some anti-CGRPs target the protein itself, while others target the receptor (blocking the pain signal).

The 6 anti-CGRPs that currently have FDA-approval are:

  • Aimovig (erenumab)
  • Vyepti (eptinezumab)
  • Emgality (galcanezumab)
  • Ajovy (fremanezumab)
  • Nurtec (rimegepant)
  • Ubrelvy (ubrogepant)

Other treatment options for managing migraine pain include:

Anti-CGRP tablets have proven effective at reducing pain of migraine both with and without aura, and in general are better-tolerated than triptans and ergot alkaloid medications.

Triptans and ergot alkaloid are known to cause overuse headaches. People with cardiovascular disease or high blood pressure usually can’t take them due to risk of side effects.

Neuromodulation devices are also considered a safe and non-invasive migraine treatment method. They may be particularly appealing to patients who have not responded to migraine medications, or who had adverse side effects.

These devices are placed or worn on different parts of the body, and release electromagnetic currents to stimulate nerves. The aim is to disrupt nerve pathways that cause pain.

The FDA has approved certain neuromodulation devices for treating migraine symptoms:

  • Cefaly (device placed on forehead)
  • Nerivio (device wrapped around upper arm)
  • Relivion MG (device placed around head)
  • gammaCore (device applied to neck)

Botox injections and hormone treatment are also used in the management of migraine episodes.

Certain medications have also been found successful at helping prevent migraine attacks. These include:

  • beta-blockers
  • antiepileptics
  • calcium channel blockers
  • antidepressants

Many people with migraine seek out home remedies or holistic therapy approaches, including acupuncture and supplements. Some people also benefit from practicing stress management techniques and talking with a therapist.

Reach out to your doctor if:

  • you experience recurring headaches that interfere with your daily life
  • your headaches come with vision or sensory changes, or nausea
  • you have migraine and believe the flu triggered a migraine episode
  • your flu symptoms are all gone, but you still have a headache or migraine episodes

It’s important to rule out other infections or health conditions when evaluating a headache or migraine attack.

Secondary headaches are common flu symptoms, but these should not be debilitating. Normally, headache as a flu symptom resolves as your nasal congestion improves.

Not everyone who contracts the flu virus (influenza) needs to go to a doctor’s office. Make sure you quarantine to prevent transmitting the virus, get plenty of rest, and drink lots of fluids. Contact your doctor to check in about symptoms. They may prescribe you medication to take home, or they may want to evaluate you.

Regardless of whether you have flu, migraine, or both, certain symptoms may be signs of a medical emergency. Contact emergency services if you are having:

  • trouble breathing
  • loss of consciousness
  • seizure
  • chest pain
  • confusion

An illness like the flu puts a lot of stress on your entire body. If you already have a migraine disorder, contracting the flu virus and developing the flu may trigger or worsen a migraine episode.

Secondary headaches can also occur as a common flu symptom, but these usually resolve with treatment and are not as severe as migraine episodes. Treating flu symptoms like fever and nasal congestion may help reduce your likelihood of headache.

If you have both a migraine disorder and the flu, treatment for both is likely needed to improve any headache you have.

Talk with your doctor if you’re experiencing any headaches that impair your functionality, regardless of whether you have the flu.