Doctor's Notes on How Do You Know If a Child Is Dehydrated?
Dehydration is when the body loses too much water and electrolytes (minerals in the blood that support body functions). Dehydration in children may be causes by any condition that causes the body to lose too much fluid and electrolytes, such as fever, sweating, diarrhea, or vomiting. Children who have an illness also may become dehydrated if it is hard for them to drink fluids.
Signs and symptoms of dehydration in children include thirst, lethargy, dry mouth, sunken eyes, dry and cool skin, drowsiness, dizziness, ore irritability. In babies, associated symptoms can include a sunken appearance to the soft spot (fontanelle) on the head or fewer soaked diapers than normal. Older children may urinate less than normal and have dark urine.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.