Signs of Dehydration: 9 Symptoms & How to Treat

Signs of dehydration include a severe headache, tiredness, intense thirst, dry mouth, urinating less than usual, cramps, dizziness, dark circles under the eyes, sunken eyes, and crying without tears. These symptoms occur when the body does not have enough water to function properly.

Dehydration happens when the body loses more water than it takes in. This can happen after spending too much time in a hot environment, exercising very intensely, or having ongoing vomiting or diarrhea.

Dehydration is more common in children and older adults because their bodies are less able to maintain fluid balance. They may not notice when they are thirsty, have smaller fluid reserves, and regulate body temperature less effectively.

Dehydration symptoms

The main symptoms of dehydration are:

1. Constant, intense thirst
2. Severe headache
3. Dry mouth
4. Dizziness
5. Sunken eyes
6. Urinating less than usual
7. Dark, strong-smelling urine
8. Muscle pain
9. Cramps

Symptoms can vary depending on the degree of dehydration:

1. Mild dehydration

The first symptoms of dehydration are usually:

• Constant thirst

• Oliguria, which is a decrease in the amount of urine

• Dark yellow, strong-smelling urine

• Dry mouth

• Headache

• Dizziness and weakness

Mild dehydration is typically easy to treat by simply increasing fluid intake.

2. Moderate dehydration

As dehydration worsens without treatment, additional symptoms may appear. These are usually signs of moderate dehydration and can include:

• Muscle pain

• Cramps

• Loss of balance

• Worsening headache

• Nausea

For moderate dehydration, it is also recommended to drink an oral rehydration solution, such as Pedialyte, which is sold in pharmacies. This helps replace both fluids and minerals.

According to the American Academy of Pediatrics, oral rehydration solutions remain an important treatment option for mild to moderate dehydration in children.

3. Severe dehydration

In severe cases, when the body loses more than 10% to 15% of its water, symptoms can worsen and may include:

• Lack of sweating

• Decreased heart rate

• Rapid breathing

• Dark circles under the eyes

• Peristent, low-grade fever

In more vulnerable populations, such as children and older adults, delirium and fainting may also occur.

In these cases, treatment usually needs to be done in the hospital with fluids given directly into a vein. Treatment should be started as soon as possible to prevent serious complications.

Dehydration in babies and children

Signs of dehydration in babies and children are:

• Crying without tears

• Sunken eyes

• Dry skin

• Rapid breathing

• Irritability

• Excessive sleepiness

• Little urine in the diaper, urinating fewer than 5 times per day, or urine with a very strong smell

• A soft spot (fontanelle) that feels softer than usual when touched

In older children, dehydration may cause trouble concentrating, difficulty learning at school, and less interest in playing.

Confirming a diagnosis

Dehydration is diagnosed by a primary care provider or pediatrician. The diagnosis is usually based on symptoms, medical history, and a physical exam.

To determine how severe the dehydration is, a healthcare provider may order blood tests to measure electrolyte levels, such as sodium and potassium, as well as urea and creatinine. A urine test may also be used to evaluate urine concentration and volume.

Dehydration treatment

Treatment for dehydration depends on the patient's age. In adults and children, rehydration usually involves drinking plenty of fluids, such as water, tea, fruit juice, milk, and soup.

Eating water-rich foods, such as tomatoes and watermelon, may also help with hydration. For people who have difficulty swallowing, thickened liquids or gelatin may be recommended to help maintain fluid intake.

Oral rehydration solution may also be used to replace fluids and electrolytes. In severe cases, treatment may be given in the hospital with fluids administered directly into a vein.