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28 Reasons for a Light or Severe Headache and Nausea

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Last updated March 22, 2024

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We might not be able to save you from a headache, but we have compiled a list of 28 reasons for a sudden headache, whether it's a temporary and random headache after eating or a worrisome headache born from an illness. Hopefully, this guide can save you from the headache of a long and complicated search.

If are really worried, addition to browsing the high-risk reasons below, also check out what a renowned Harvard doctor says about when to worry about a headache. We also prepared a quiz from our that quickly evaluates your headache, accurately and personalized to your symptoms.

Lastly, if you're looking for headache relief, head over to How to Stop a Headache: 23 Methods for Fast Headache Relief.

Are your headaches dangerous?

Headaches are just as common as simple colds. 90% of all headaches are low-risk and won’t cause your body any serious harm. But 10% of headaches are signs or symptoms of a condition that requires prompt medical attention.

You need two pieces of information to better determine if your headaches are dangerous. First, browser through the list of headache types in this article, which have been broken down into three categories.

  • Low Risk:

These types of headaches are treated with over the counter pain medication or just by waiting them out. We have a great list of headache treatments you can try here.

  • Medium Risk:

These are types of headaches that you should closely monitor. While there’s a better chance that they’re simply a nuisance rather than a danger, the pain can be intense and quickly turn to debilitating. Monitor your symptoms and if you don’t notice improvement within a reasonable time frame, seek medical attention.

  • High Risk:

If your type of headache falls under the severe risk category, get immediate medical attention. These types of headaches are usually a symptom of a serious or even life-threatening condition that won’t go away on its own.

Second, you need to know what characteristics of a headache are concerning and when to worry about your headache. In that article, a renowned Harvard doctor explains what factors are signs of concern.

Low risk types of headaches

Easily managed with over-the-counter (OTC) medications

1. Tension headaches

Tension headaches are the most common type of headache. Symptoms include a dull pain that is constant instead of throbbing and feels like a tight band of pain around the head. Emotional stress can be a cause, along with depression or tight muscles. These types of headaches usually go away on their own but the use of over the counter pain medication, hot and cold treatments, or relaxation can help treat and prevent tension headaches.

2. Dehydration and headaches

It’s common knowledge that eight glasses of water are a daily requirement yet most people don’t hit that mark. When your body doesn’t have enough fluid, a dehydration headache can kick in and vary from mild to severe. This type of headache is caused by a temporary contraction in the brain due to fluid loss. If you’re suffering from extreme thirst, dizziness, fatigue, or reduced urination dehydration could be to blame. Increase your daily water intake slowly but consistently for relief and prevention of a dehydration headache.

3. Exertion headaches

If you just went for a run, worked out, or were chasing after the kids, a headache with quick onset can be classified as an exertion headache. If you notice a headache trend after strenuous activities, look for alternative exercise methods or proceed with your daily tasks at a slower pace. Exertion headaches can usually be treated with over the counter pain medication but if they persist, see your doctor.

4. Headaches from common cold

If you have a cold, there’s a good chance you’ll develop a headache as a symptom. One study found that more than 60% of cold sufferers developed a headache along with their other common cold symptoms, which include a runny nose, sore throat, chills, and a cough. When you have a cold, cytokines are released in the body. These molecules are an important part of your body’s immune defense and while they work to fight your cold, they can cause headaches. Over the counter cold medication helps, but rest and an increase in fluid intake is also recommended.

5. Hangover headache

If you had one too many glasses of wine with dinner or stayed at the bar with your friends until closing time, you might wake up with a pounding headache as a reminder of the previous night’s excitement. A hangover headache consists of throbbing pain and sometimes nausea and fatigue caused by the irritation of blood vessels in the brain. The best prevention for a hangover headache is to drink in moderation but if the damage has already been done, increase your liquid intake and take it easy.

6. Stomach flu headaches

Gastroenteritis, or stomach flu, is caused by a virus that inflames the stomach and intestines. There are plenty of not-so-friendly symptoms associated with the stomach flu, like nausea, vomiting, and diarrhea, which can all lead to dehydration. As previously mentioned in this guide, dehydration headaches can vary from mild to severe but can feel worse due to other symptoms of the flu, like fatigue and fever. In most cases, the stomach flu resolves on its own, as should your headache. But if symptoms persist for more than a few days, seek medical attention to prevent serious complications.

7. Sinus pressure headaches

When the nasal passages become blocked or inflamed, a sinus pressure headache can occur. This type of headache is one of the most misdiagnosed, with migraines and cluster headaches often first being diagnosed as sinus-related. Sinus headaches are usually caused by infections but can also develop due to nasal polyps or a deviated septum. If an infection is to blame, your doctor can prescribe antibiotics.

8. TMJ headaches and symptoms

TMJ headaches are related to the temporomandibular joint, the joint responsible for opening and closing the jaw. If your headache is TMJ-related, you might notice a painful clicking-sound each time you open your mouth. Sometimes, the way your teeth line up when biting causes stress on this joint, leading to a headache. Other times, stress is a factor, especially if it causes you to clench your jaw. The use of a bite plane or nightguard can help both treat and prevent TMJ-related headaches. You can try over the counter bite planes or nightguards but if they don’t work well enough, your dentist can custom-make one for you.

9. Seasonal allergy headaches

If a change in seasons coincides with your headache, it is likely a result of seasonal allergies or other environmental irritants. With more pollen, mold, and other irritants in the air, you might experience watery and itchy eyes, nasal congestion, sneezing, or a generalized headache. Most people are able to manage allergies with an over the counter antihistamine medication. If you find that seasonal allergies and headaches are having a profound effect on your quality of life, there are other options, like injections, that can be prescribed by your doctor.

10. Headaches from mold

Mold can be a silent and sometimes invisible culprit of headaches. If you’re allergic to mold, you might experience sneezing, nasal congestion, postnasal drip, itchy eyes, and mild to severe headaches. Headache pain due to mold usually forms below the eyes, in the forehead, or in the front of the head. Mold allergies can be dangerous, so if you suspect they are the cause of your headaches, eliminate the presence of mold in your home. This could require professional services.

11. Headache from too much sleep

Vacations and weekends are a great time to catch up on some much-needed sleep, but as the saying goes, you can have too much of a good thing. While it’s not certain why oversleeping causes headaches in some people, most researchers believe that this type of headache is a side effect of altered levels of neurotransmitters in the brain. The best prevention of this type of headache is to keep a similar sleep schedule on all days of the week and avoid napping for prolonged periods during the day.

12. Caffeine withdrawal headaches

If you’re trying to kick your morning joe habit, be prepared for a few caffeine withdrawal headaches. Symptoms include a throbbing head, which is caused by rebounding blood vessels. These headaches can last for several days but will eventually go away on their own. Consuming caffeine will treat the headache, but the pain can quickly set in again over the next few days. Everyone reacts to caffeine differently so if you notice the development of headaches on days when you don’t consume caffeine, you might want to eliminate your consumption altogether.

13. Headaches after sex

Just as the name suggests, these types of headaches are brought on by sexual activity. While they’re more of a nuisance than a serious medical condition, some can be a sign of damaged blood vessels in the brain. If you experience headaches on a regular basis either after an orgasm or during sexual excitement, take note of their intensity. Most only last several minutes and resolve on their own, with the condition disappearing completely after several months of first developing.

Usually managed as an outpatient by your doctor with prescription medication

14. Migraine headaches

Migraines are severe headaches that are described as an intense throbbing pain on one side of the head. Other symptoms include nausea, vomiting, and sensitivity to light and sound. Migraines can be hereditary or caused by certain foods, stress, or even the weather. If you suffer from migraines frequently, medical intervention is recommended to determine the exact cause and to develop a treatment and prevention regimen. A prescription is often necessary.

15. Mononucleosis headaches

Commonly known as “the kissing disease”, mononucleosis is a viral infection usually spread by saliva. It’s mostly contracted by teenagers but it can affect adults of any age. Symptoms include a sore throat, swollen lymph glands, and a fever. A headache is also a common symptom. A blood test is required for a proper diagnosis and treatment is usually mild, including getting plenty of rest, increasing fluid intake, and taking over the counter pain medication.

16. Fibromyalgia headaches

Fibromyalgia is a syndrome that includes symptoms like generalized pain, morning stiffness, trouble sleeping, fatigue, numbness, anxiety, and depression. In 40% of people with fibromyalgia, headaches are not just common but chronic. These headaches are usually caused by pain in the back or neck, specifically by tightness and contractions of certain muscles. If you have been diagnosed with fibromyalgia and suffer from headaches on a regular basis, speak to your doctor about treatment options.

17. Headaches from dieting and food intake

What we eat (or don’t eat) can be a cause of headaches. When dieting or cutting calories, low blood sugar can bring on a headache. If you’re trying to lose weight, focus on having frequent but smaller meals. A lack of magnesium can also be a headache cause. You can supplement your magnesium intake but stay within the daily recommendation, because an excess of magnesium can also cause headaches. Avoid consuming too much sugar or sodium, as both can lead to headaches as well. If you suffer from chronic daily headaches, keep a food journal for a couple weeks to see if you notice trends based on your diet.

Medium risk types of headaches

May require an ED visit or hospitalization. Precription medication needed usually.

18. Pregnancy headaches

Pregnancy comes with a long list of side effects, commonly including headaches throughout all three trimesters. During the first trimester, headaches can be blamed on an increase in blood volume and changing hormone levels. Lack of sleep, dehydration, and stress, both emotional and physical, can cause headaches as well. But if you have an intense headache, especially during the third trimester, speak to your doctor as this can be a sign of preeclampsia, a serious condition that can be fatal for both mother and child.

19. Menopause headaches

Just as monthly menstruation can cause headaches, so can menopause. Again, the cause of these headaches is hormonal. For some women, they might experience relief from period headaches as menopause sets in. But for others, the frequency and intensity of the headaches can increase. Estrogen patches, which require a doctor’s prescription, can be used to help prevent or relieve menopause headaches if they are occurring on a regular basis.

Hospitilization needed, usually not life threatening but could be

20. Cluster headaches

A cluster headache is a severe headache that typically presents itself on only one side of your head. The pain is frequently described as burning or sharp and occurs with eye tearing or runny nose. This type of headache can be short, lasting less than half an hour, or radiate for several hours before subsiding. Cluster headaches get their name because of their short and close bursts of pain. Once the pain subsides, it can come back quickly. Those who suffer from cluster headaches are likely to experience these daily. A tell-tale sign of a cluster headache is a red, swollen eye. You might notice drooping in the eyelid and your nose might become stuffy. If you’re experiencing cluster headaches on a regular basis, see your doctor.

21. Wisdom teeth headaches

A wisdom teeth headache can either be caused by the emergence of wisdom teeth or by their removal. If you have just had your wisdom teeth removed, prescription-strength pain medication should help as your body heals. If the headaches persist, speak to your oral surgeon. But if your wisdom teeth are still present, they can cause headaches as they try to erupt. If there isn’t enough room for your wisdom teeth, they can push other teeth, misalign your bite, or put pressure on jaw joints. A dental x-ray should quickly determine if your wisdom teeth need to be removed.

High risk types of headaches

Life threatening and death is possible. Intensive Care Unit (ICU) care often needed.

22. Encephalitis headaches

Encephalitis is the presence of inflamed brain tissue caused by the immune system mistakenly attacking brain tissue. It is most often caused by a viral infection. A headache that develops suddenly is a common symptom, along with fever, severe sensitivity to light, fatigue, muscle aches, and fever. More severe symptoms include seizures, muscle weakness, and confusion. Encephalitis can be life-threatening and permanent complications can arise, like speech impairments and paralysis. If you suspect this is the cause of your headache, go to an urgent care clinic or the emergency room immediately.

23. Meningitis

Meningitis, which is an inflammation of the outer lining of the brain, can be caused by bacteria, fungi, or a virus. There are vaccines that protect against some but not all types of meningitis. Some of the first symptoms to develop are a fever, vomiting, an overall sense of feeling unwell, and a headache. As the illness progresses, more serious symptoms appear include pain in the limbs, cold hands and feet (extremities), and pale skin. See your doctor immediately. Depending on what caused the illness, treatment can vary from simple rest and pain management to serious life-saving interventions.

24. Headache due to brain bleed

Bleeding in the brain can be brought on by a ruptured aneurysm caused by weakness in the wall of a blood vessel. Some aneurysms can remain asymptomatic and cause no symptoms. But larger aneurysms can rupture, leading to bleeding in the brain. This causes an intense headache that can’t be ignored, along with difficulty speaking, blurred vision, drooping of the eyelid(s) or one side of the face, and dilated pupils. If you have any of these symptoms and it developed abruptly, seek medical attention immediately.

25. Brain tumor

Tumors in the brain can be benign or malignant but almost always need immediate medical attention. As the tumor grows, headaches can be one of the first symptoms. Other signs of a brain tumor include visual disturbances, trouble speaking, personality changes, seizures, or violent vomiting. The cause of brain tumors isn’t completely understood but treatment has advanced in recent years. Surgery or radiological treatment can eliminate the tumor and the related symptoms.

26. Brain abscess

A brain abscess is caused by a fungal or bacterial infection. A sac of pus forms in the brain tissue and although a brain abscess is quite rare, it can be very serious. More than three-quarters of people with a brain abscess develop a dull headache and for some, this is the only symptom of its presence. The pain is generally local, based on where the abscess is, and increases until treatment is administered. Pain medication will not help brain abscess headaches. Treatment usually involves antibiotics or drainage.

27. Thunderclap headaches

A thunderclap headache is a serious type of headache that requires immediate medical attention. These types of headaches strike suddenly and quickly. Unlike more common types of headache, pain doesn’t grow gradually. Instead, the headache reaches full intensity in a matter of seconds and does not improve. A thunderclap headache is usually a symptom of a life-threatening condition, like meningitis, an aneurysm, or a brain hemorrhage. If you’re experiencing a headache like nothing you’ve ever felt before, it’s best to be evaluated by a doctor immediately.

28. Headache as a stroke symptom

Well-known stroke symptoms include difficulty walking, trouble speaking, and numbness of the face or limbs. But another symptom to look out for is a headache. Strokes occur when the brain’s blood flow is interrupted. One type of a stroke, called a hemorrhagic stroke, happens when there is bleeding in the brain due to a ruptured blood vessel (aneurysm explained above is one of a few causes of a hemorrhagic stroke, see the difference between stroke and aneurysms). In approximately one-third of patients who experience this type of a stroke, a severe headache was a symptom. If you experience a quickly developing and intense headache, seek medical attention immediately.

Though we can’t prevent all types of headaches, we can treat most types quickly and safely. The next time you start to feel a headache coming on, focus on determining its type for faster relief.

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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
Dr. Peter Steinberg is a board-certified urologist and the director of endourology and kidney stone management at Beth Israel Deaconess Medical Center. He is also an Assistant Professor at Harvard Medical School. He received his undergraduate degree in biochemistry from Middlebury College (1999) and graduated from University of Pennsylvania Medical School (2003). He completed a urology residency a...
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