About this symptom
Children can lose fluid rapidly during diarrhoea, repeated vomiting, fever or when they cannot drink enough. Dehydration is assessed by several signs together, not by thirst or the absence of tears alone.
What matters most
A dry mouth, fewer wet nappies or trips to the toilet, sunken eyes, unusual tiredness and reduced tears may indicate fluid loss. In infants, refusal to feed or a sunken soft spot can also be concerning. Age and current illness change how symptoms are interpreted.
Symptoms and situations to watch
Keep track of drinking, vomiting, number and type of stools, the child’s alertness and the frequency of urination. Fast breathing, cold or mottled skin, pronounced drowsiness or difficulty waking the child suggest a potentially severe condition.
Important distinctions
Mild dehydration in a child able to drink may be managed differently from severe dehydration or shock. Ordinary water does not replace salts lost with significant diarrhoea; sugary soft drinks are not an appropriate replacement for oral rehydration solution.
How clinicians assess the problem
A clinician assesses circulation, breathing, mucous membranes, behaviour, urine output and the likely source of fluid loss. Tests and intravenous fluids are used when indicated, not automatically for every episode of gastroenteritis.
Care and limitations
For a child who is awake, able to swallow and without danger signs, an age-appropriate oral rehydration solution may be offered in small frequent amounts, following medical guidance. Breastfeeding is generally continued. Avoid unsupervised anti-diarrhoeal medicines.
When emergency help is needed
Call 103 or 112 for loss of consciousness, difficulty waking, severe breathing problems, cold mottled skin or signs of shock. If the child cannot keep fluids down, has almost no urine or is worsening, arrange urgent in-person care rather than waiting for a routine visit.
Related information
Blood in a child’s stool; Poor weight gain in a child; Sore throat in a child.
Signs and symptoms
Keep track of drinking, vomiting, number and type of stools, the child’s alertness and the frequency of urination. Fast breathing, cold or mottled skin, pronounced drowsiness or difficulty waking the child suggest a potentially severe condition.
Diagnosis and tests
A clinician assesses circulation, breathing, mucous membranes, behaviour, urine output and the likely source of fluid loss. Tests and intravenous fluids are used when indicated, not automatically for every episode of gastroenteritis.
Care and treatment approaches
For a child who is awake, able to swallow and without danger signs, an age-appropriate oral rehydration solution may be offered in small frequent amounts, following medical guidance. Breastfeeding is generally continued. Avoid unsupervised anti-diarrhoeal medicines.
When to seek urgent care
Call 103 or 112 for loss of consciousness, difficulty waking, severe breathing problems, cold mottled skin or signs of shock. If the child cannot keep fluids down, has almost no urine or is worsening, arrange urgent in-person care rather than waiting for a routine visit.
Frequently asked questions
Do no tears always mean dehydration?
No. Reduced tears are one clue, which must be considered with urine output, drinking, energy level and other symptoms.
Can plain water replace oral rehydration solution?
With diarrhoea or vomiting, both water and salts may be lost. The suitable fluid depends on age and severity; an oral rehydration solution is often advised.
When is an ambulance necessary?
Unresponsiveness, extreme drowsiness, breathing difficulty, suspected shock or rapid deterioration warrant 103 or 112 immediately.
Important information
A medical consultation is needed for diagnosis and treatment recommendations.
Self-treatment can be harmful to your health.
