Dehydration: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Dehydration?
A primary care doctor, such as a family medicine or internal medicine doctor, can treat mild dehydration, which means the body has lost too much fluid. A pediatrician, a children's doctor, cares for infants and children. Severe dehydration may be treated in a hospital. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is dehydration?
Dehydration is a condition caused by the loss of too much fluid from the body. It happens when you lose more fluid than you take in. Then your body does not have enough fluid to work properly.
Dehydration can be mild, moderate, or severe. Severe dehydration is a life-threatening emergency.
Symptoms
In adults, the symptoms of dehydration include:
- Feeling very thirsty.
- Dry or sticky mouth.
- Urinating and sweating less than usual.
- Dark-colored urine.
- Dry skin, headache, or muscle cramps.
- Feeling tired or dizzy.
Signs of severe dehydration include very dark urine or no urine, sunken eyes, fast heartbeat, fast breathing, confusion, and shock. Shock means not enough blood is flowing through the body.
In infants and young children, the symptoms include:
- Dry mouth and tongue.
- Crying without tears.
- No wet diapers for 3 hours or more.
- A high fever.
- Being unusually sleepy or drowsy, or being irritable.
- Eyes that look sunken.
Causes and who gets it
You can become dehydrated if you lose too much fluid, do not drink enough, or both. Fluid is lost through diarrhea, vomiting, fever, and too much sweating. You can also lose a lot of fluid by urinating too much. Uncontrolled diabetes or some medicines, like diuretics, can cause this.
You may drink too little when you are sick. You might feel nauseated, have a sore throat, or have mouth sores.
Some people are more likely to become dehydrated:
- Older adults. Some people lose their sense of thirst as they age.
- Infants and young children, who are more likely to have diarrhea or vomiting.
- People with long-term illnesses that make them urinate or sweat more often, such as diabetes, cystic fibrosis, or kidney problems.
- People who exercise or work outdoors in hot weather.
How doctors diagnose it
To find out if you are dehydrated, your health care provider will do a physical exam, check your vital signs, and ask about your symptoms.
The provider looks for low blood pressure, blood pressure that drops when you stand up, and a fast heart rate. Skin that is not as elastic as normal is another sign. When pinched into a fold, it may sag back slowly.
Your provider may also order blood tests to check kidney function and electrolyte levels. Electrolytes are minerals in your body that have an electric charge. Urine tests can help show the cause.
Treatment
The treatment for dehydration is to replace the fluids and electrolytes you have lost. For mild cases, you may just need to drink lots of water. If you lost electrolytes, sports drinks may help.
For children, there are oral rehydration solutions, which are drinks that you take by mouth to replace lost fluids. You can buy them without a prescription. Do not take salt tablets, because they can cause serious complications.
Severe cases may be treated in a hospital with intravenous (IV) fluids, which go into a vein. Your provider will also treat the cause of the dehydration. Dehydration caused by a stomach or intestinal virus should get better on its own after a few days. If you notice signs of dehydration and treat it quickly, you should recover completely.
When to see a doctor
Call 911 or your local emergency number if the person loses consciousness at any time. Also call if there is any other change in alertness, such as confusion or seizures. Call for shock, a rapid heartbeat or rapid breathing, or no urine. Call if the person has a fever over 102 degrees F (38.8 degrees C), or if the condition does not improve or gets worse despite treatment.
If someone in your family is at risk of becoming dehydrated, call your provider before it happens.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either can check for dehydration, order blood and urine tests, and look for the cause, such as diabetes or a medicine. They can also follow up with you and refer you to a hospital if needed.
Common questions
Can dehydration be prevented?
Yes, the key to preventing dehydration is making sure you get enough fluids. Drink enough water every day, and drink extra when the weather is hot or you are exercising. Each person's needs can be different, so ask your provider how much you should drink. Get extra fluids when you are sick.
What happens if severe dehydration is not treated?
Untreated severe dehydration may cause death, permanent brain damage, or seizures.
How can I tell if my child is dehydrated?
Signs in infants and young children include crying without tears, no wet diapers for 3 hours or more, and a dry mouth and tongue. Other signs are a high fever, unusual sleepiness, irritability, and sunken eyes.
What should I drink if I am dehydrated?
For mild dehydration, water is often enough. Sports drinks may help if you lost electrolytes. Some sports drinks have a lot of sugar, so do not drink too much of them.
Sources
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
