Read the outputs and the energy: dark strong-smelling pee, peeing less (fewer wet diapers in babies), dry mouth, no tears, sunken eyes, listlessness - the NHS sign list.
Small bodies dehydrate fast with vomiting, diarrhea, or fever, so respond immediately: small frequent sips or oral rehydration solution, continued breast or formula feeds in infants, no undiluted juice or soda. The escalation lines: no wet diaper for 8-plus hours, lethargy replacing thirst, vomiting that keeps even sips down, sunken soft spot - same-day care, and urgent under age 1.
What to do
Common questions
How do I know if my child is dehydrated?
Dehydration in kids is read from outputs and behavior more than complaints - toddlers cannot report thirst usefully. The NHS sign list: dark yellow, strong-smelling pee; peeing less often than usual (in babies, fewer wet diapers - the cleanest home metric: count them against normal); a dry mouth, lips, and tongue; no tears when crying; sunken eyes (and in babies, a sunken soft spot); tiredness and listlessness beyond the illness; dizziness in older kids. The situations that create it: vomiting, diarrhea, fever, and refusing fluids - and small bodies dehydrate fast, so the response is immediate: small, frequent sips of fluid or an oral rehydration solution (the pharmacy kind, formulated for this), continuing breastfeeding or formula in infants, and avoiding undiluted juice or soda, which worsen diarrhea. The escalation lines: no wet diaper for 8-plus hours, signs moving from thirsty to lethargic, vomiting that keeps even small sips down, or the sunken-eyes and soft-spot signs - those are same-day medical care, and a baby under 1 with these signs is urgent. Pymander, a free AI doctor available 24/7 by text, can help you judge the signs right now.