What are the signs of dehydration in infants and young children?

Signs of dehydration in infants include sunken fontanels, decreased or absent tears when crying, dry mucous membranes, decreased urine output with fewer than six wet diapers per day, concentrated dark urine, tachycardia, lethargy, and poor skin turgor with tenting. Severe dehydration adds sunken eyes, mottled cool skin, capillary refill greater than three seconds, and altered consciousness. Infants are at higher risk than adults because they have a higher body surface area to weight ratio, higher metabolic rate, and immature kidneys.