When you feel a headache (or fatigue, dizziness, or mental fuzziness) come on, you may be quick to assume you’re dehydrated. Not so fast. While it’s true that these symptoms are some of the indicators that you’re not getting enough fluids, that may not be the only thing your body is trying to tell you.
Here are seven medical conditions that could be the real underlying issue.
1. Heatstroke
“Many of the same symptoms of dehydration arise when an individual is experiencing heatstroke,” says Garth Graham, MD, MPH, a cardiologist and the director and global head of healthcare and public health at Google. Those overlapping symptoms include dizziness, confusion, and headache.
But pay attention to other indicators of heatstroke: a body temperature of at least 104 degrees F, nausea, and a racing heart rate. Dehydration and heatstroke also share some causes, such as hot weather and strenuous activity — and, to add to the confusion, being dehydrated sometimes leads to heatstroke.
“Being able to tell them apart is vital,” Dr. Graham says. That’s because the seriousness of the conditions varies significantly. You don’t usually need to seek medical attention for mild dehydration because you can rehydrate on your own, but heatstroke can be deadly and is “not a health issue to be light about,” Graham says.
Call 911 if you or someone nearby appears to be suffering from heatstroke. As you wait for help to arrive, move to a cool place and do whatever you need to do to cool down, whether by dumping cold water on your body or removing excess clothing.
2. Stroke
Severe dehydration can lead to confusion, but confusion may also be a sign of a stroke, says Sean Hashmi, MD, a board-certified internist, nephrologist, and obesity medicine specialist practicing at Kaiser Permanente in Southern California.
So how can you tell what’s really going on? Look out for symptoms unique to stroke patients.
Someone having a stroke may slur his or her words, experience numbness on one side of the body, or have trouble walking. When in doubt, call on a doctor for an expert opinion.
“Whenever there’s a change in how a person normally behaves — and this is incredibly important among people who are older — you want to make sure you get that person evaluated so we’re not just writing it off as dehydration and, God forbid, missing something like a stroke,” Dr. Hashmi says.
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3. Concussion
Concussion, like dehydration, can cause headaches. As far as children are concerned, Dana Cohen, MD, an integrative medicine doctor based in New York City, says it’s important for them to be hydrated before a doctor evaluates them for concussion.
“When a doctor is trying to diagnose a concussion in a kid, which has symptoms including dizziness and headache, it’s hardly ever taken into account that dehydration has very similar symptoms,” Dr. Cohen says. “You may be misdiagnosed with a concussion early on when you were just dehydrated.”
Or vice versa: Concussion can be mistaken for dehydration. Concussions require emergency care if accompanied by vomiting, changes in behavior and coordination, or a loss of consciousness that lasts longer than 30 seconds.
4. Menopause
Like dehydration, menopause is usually accompanied by symptoms such as irritability and dryness.
“If you’re losing estrogen, you’re drying out all over the place,” Cohen says.
Hashmi says dehydration can lead to dry skin that loses its elasticity. But if you’re a woman in your forties or fifties and notice dryness in the vaginal region, and perhaps also experience irregularities with your period, menopause could be to blame.
“That could be something to look into if you know you’re hydrating properly and [the dryness doesn’t go away],” Cohen says.
5. Sjögren’s Syndrome
Dry mouth can be the body’s way of telling you to take in more fluids. But the eyes also have a lot to say when it comes to hydration.
Cohen says if you notice an uptick in how many eye drops you’re using, it could be Sjögren’s syndrome. This autoimmune disorder usually occurs in women older than 40. Your eyes will likely also burn, itch, or feel like there’s sand in them.
Your doctor will likely measure your tear production and check for a damaged cornea, which may indicate Sjögren’s syndrome and not dehydration.
6. Liver Disease
Talk to any hydration expert and he or she will tell you to pay attention to the color of your urine to know how hydrated you are. Pale yellow? You’re in the clear. But a dark color could be a sign you’re in need of some water. Or, it could indicate a problem with your liver.
When bile is being blocked inside or outside the liver, which is called cholestasis, your urine may be darker than usual. Be on the lookout for other signs that something’s not right with your liver, such as pale stools or a yellow tint to your skin and eyes, which are signs of a condition called jaundice.
7. Hypothyroidism
Low thyroid hormone production, aka hypothyroidism, can result in dry skin and constipation, which overlap with signs of dehydration, Cohen says. Other symptoms the two conditions share are fatigue and confusion. Dehydration can happen to anyone, though the risk is much higher for young children and elderly people.
The condition occurs when the body’s thyroid gland isn’t working properly, and it’s something you’ll want to get checked out. If left untreated, it could lead to infertility, obesity, or heart disease, among other conditions.
The Takeaway
If you experience symptoms such as a headache or dizziness, dehydration may not be the only cause.
These symptoms can overlap with other potential issues such as stroke, heatstroke, or thyroid problems.
Stay hydrated and talk with your doctor if your symptoms persist.
FAQ
What are some common symptoms of dehydration?
Common symptoms of dehydration include headache, dizziness, tiredness, thirst, dry mouth, crankiness, dark urine, dry skin, and constipation.
How can you differentiate between heatstroke and dehydration?
Heatstroke and dehydration share some symptoms, such as dizziness, confusion, and headache. But signs of heatstroke include a body temperature of at least 104 degrees F, nausea, and a racing heart rate.
What symptoms are unique to stroke patients and are not symptoms of dehydration?
Like dehydration, stroke can cause confusion. But symptoms unique to stroke patients include slurred speech, numbness on one side of the body, and difficulty walking.
How can dehydration and concussion have similar symptoms?
Dehydration and concussion can have similar symptoms, such as dizziness and headache. This can lead to misdiagnosis, so it's important to consider hydration levels when evaluating a possible concussion.
What are some symptoms of liver disease that may be mistaken for dehydration?
Dark urine is a symptom of liver disease that may be mistaken for dehydration. Pale stools and a yellow tint to the skin and eyes (jaundice) may also indicate a problem with the liver.
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Allison Buttarazzi, MD, is board-certified in internal medicine and lifestyle medicine, and is a certified health and well-being coach. In her primary care practice, Dr. Buttarazzi focuses on lifestyle medicine to help her patients improve their health and longevity, and her passion is helping patients prevent and reverse chronic diseases (like heart disease, high blood pressure, and diabetes) by improving their lifestyle habits.
She is a graduate of Tufts University School of Medicine and completed a residency at Maine Medical Center. Diagnosed with celiac disease during medical school, she realized the power of improving one's health through diet and lifestyle habits, which she later incorporated into her practice.
Moira Lawler is a journalist who has spent more than a decade covering a range of health and lifestyle topics, including women's health, nutrition, fitness, mental health, and travel. She received a bachelor's degree from Northwestern University’s Medill School of Journalism and lives in the Chicago suburbs with her husband, two young children, and a giant brown labradoodle.
