Heat Illness in Children: A Growing Concern
Content reviewed against published AAP, CDC, WHO guidelines
Last reviewed:
If your baby has been diagnosed with or you suspect heat illness in children: a growing concern, here is what the evidence says.
The short answer
Children, especially infants and toddlers, are more vulnerable to heat illness than adults because they produce more heat relative to body size, sweat less efficiently, and depend on caregivers for hydration and cooling. With rising temperatures, heat-related illness in children is increasing. Prevention includes keeping babies hydrated, avoiding direct sun during peak hours, never leaving a child in a parked car, and dressing them in lightweight clothing. Heat stroke is a medical emergency requiring immediate action.
Key takeaways
- Children, especially infants and toddlers, are more vulnerable to heat illness than adults because they produce more heat relative to body size, sweat less efficiently, and depend on caregivers for hydration and cooling. With rising temperatures, heat-related illness in children is increasing. Prevention includes keeping babies hydrated, avoiding direct sun during peak hours, never leaving a child in a parked car, and dressing them in lightweight clothing. Heat stroke is a medical emergency requiring immediate action.
- Usually normal when: Your baby is slightly flushed in warm weather but is feeding well, has wet diapers, and is behaving normally.
- Call your doctor if: Your child has a body temperature above 104 degrees F (40 degrees C), is not sweating, has hot and dry skin, or is confused or losing consciousness (signs of heat stroke).
- Varies by age — see the age-by-age breakdown below
“Fever itself is not an illness — rather, it is a sign or symptom that the body is fighting an infection. Fever stimulates certain defenses, such as the white blood cells, which attack and destroy invading bacteria.”
This is one of the most common questions parents ask. Searching for answers means you care.
When to Seek Immediate Care
- Your child has a body temperature above 104 degrees F (40 degrees C), is not sweating, has hot and dry skin, or is confused or losing consciousness (signs of heat stroke).
- Your child was left in or found in a hot car -- call 911 immediately and begin cooling.
- Your child is showing signs of severe dehydration: no tears, no wet diapers for 6+ hours, sunken fontanelle, extreme sleepiness, or inability to drink.
By Age
What to expect by age
0-6 months
Infants are extremely vulnerable to overheating because they cannot regulate their body temperature effectively. Signs of overheating include flushed skin, rapid breathing, irritability, and lethargy. Babies under 6 months should be kept out of direct sunlight. In hot weather, offer extra breastfeeds or formula feeds to prevent dehydration. Dress them in light, loose-fitting clothing. Room temperature should ideally be 68-72 degrees F (20-22 degrees C). Never cover a car seat or stroller with a blanket, as this creates a dangerous heat trap.
6-12 months
As babies become more mobile, they may be spending more time outdoors. Apply sunscreen (SPF 30+) to exposed skin, provide shade, and offer water in addition to breast milk or formula in hot weather. Watch for signs of heat exhaustion: excessive sweating followed by no sweating, pale or cool skin, nausea, and fatigue. Limit outdoor play during the hottest parts of the day (10 AM to 4 PM). Allow babies to acclimatize gradually to warmer weather over 10-14 days.
12-36 months
Active toddlers may not recognize or communicate that they are overheated. Ensure frequent water breaks during outdoor play, as toddlers can become dehydrated quickly. Pool and water play can help with cooling but requires constant supervision. Recognize that concrete, asphalt, and playground equipment can become dangerously hot and burn small feet and hands. If your child stops sweating, becomes confused, or has a very high body temperature (104 degrees F or above), this is heat stroke -- a medical emergency.
What Should You Do?
When to take action
- Your baby is slightly flushed in warm weather but is feeding well, has wet diapers, and is behaving normally.
- Your child develops mild heat rash (tiny red bumps) in skin folds during hot weather.
- Your toddler wants to drink more water than usual during hot weather and remains active and alert.
- Your baby seems more lethargic or irritable than usual in hot weather despite staying hydrated.
- Your child has recurrent heat rash that does not clear with cooling measures.
- You are concerned about adequate hydration during hot weather, especially if your child is refusing fluids.
- Your child has a body temperature above 104 degrees F (40 degrees C), is not sweating, has hot and dry skin, or is confused or losing consciousness (signs of heat stroke).
- Your child was left in or found in a hot car -- call 911 immediately and begin cooling.
- Your child is showing signs of severe dehydration: no tears, no wet diapers for 6+ hours, sunken fontanelle, extreme sleepiness, or inability to drink.
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Heat Illness in Children: A Growing Concern.
Things to mention
- Your baby seems more lethargic or irritable than usual in hot weather despite staying hydrated.
- Your child has recurrent heat rash that does not clear with cooling measures.
- You are concerned about adequate hydration during hot weather, especially if your child is refusing fluids.
Observations to share
- Your baby seems more lethargic or irritable than usual in hot weather despite staying hydrated.
- Your child has recurrent heat rash that does not clear with cooling measures.
- You are concerned about adequate hydration during hot weather, especially if your child is refusing fluids.
Urgent signs to report immediately
- Your child has a body temperature above 104 degrees F (40 degrees C), is not sweating, has hot and dry skin, or is confused or losing consciousness (signs of heat stroke).
- Your child was left in or found in a hot car -- call 911 immediately and begin cooling.
- Your child is showing signs of severe dehydration: no tears, no wet diapers for 6+ hours, sunken fontanelle, extreme sleepiness, or inability to drink.
My notes
From ismybabyalright.com — free, evidence-based baby health guides
Related Conditions
My Baby Has a Fever That Won't Go Away
Most fevers in babies and toddlers are caused by viral infections and resolve within 3-5 days. A fever that lasts longer than 3 days, returns after seeming to resolve, or is accompanied by worsening symptoms warrants medical evaluation. The most important thing is how your baby looks and acts - a child who is alert and drinking well with a fever is generally less concerning than one who is listless, regardless of the temperature.
How to Rehydrate My Baby
The best way to rehydrate a sick baby is to offer breast milk, formula, or a commercial oral rehydration solution (like Pedialyte) in small, frequent amounts. For breastfed babies, nurse more often in shorter sessions. For formula-fed babies and toddlers, offer an oral rehydration solution in small sips every few minutes. Avoid giving plain water alone to babies under six months, juice, soda, or sports drinks, as these can worsen diarrhea.
Baby Hives (Urticaria)
Hives are raised, red, itchy welts that can appear suddenly on your baby's skin. They are most often caused by a viral infection or an allergic reaction to food, medication, or an insect bite. While they can look alarming, hives are usually harmless and resolve on their own, though any breathing difficulty needs immediate emergency care.
Related Resources
Frequently asked questions
Is heat illness in children: a growing concern normal?
When should I call the doctor about heat illness in children: a growing concern?
When is heat illness in children: a growing concern normal?
What causes heat illness in children: a growing concern?
What should I mention to my pediatrician about heat illness in children: a growing concern?
Is heat illness in children: a growing concern normal at 0-6 months?
Is heat illness in children: a growing concern normal at 6-12 months?
Should I go to the ER for heat illness in children: a growing concern?
Does heat illness in children: a growing concern go away on its own?
References
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources
Related Resources
Bottom line
Most cases of heat illness in children: a growing concern are normal. Talk to your pediatrician if your child has a body temperature above 104 degrees f (40 degrees c), is not sweating, has hot and dry skin, or is confused or losing consciousness (signs of heat stroke).
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.
Was this page helpful?
Related Medical Concerns
My Baby Has a Fever That Won't Go Away
Most fevers in babies and toddlers are caused by viral infections and resolve within 3-5 days. A fever that lasts longer than 3 days, returns after seeming to resolve, or is accompanied by worsening symptoms warrants medical evaluation. The most important thing is how your baby looks and acts - a child who is alert and drinking well with a fever is generally less concerning than one who is listless, regardless of the temperature.
How to Rehydrate My Baby
The best way to rehydrate a sick baby is to offer breast milk, formula, or a commercial oral rehydration solution (like Pedialyte) in small, frequent amounts. For breastfed babies, nurse more often in shorter sessions. For formula-fed babies and toddlers, offer an oral rehydration solution in small sips every few minutes. Avoid giving plain water alone to babies under six months, juice, soda, or sports drinks, as these can worsen diarrhea.
Baby Hives (Urticaria)
Hives are raised, red, itchy welts that can appear suddenly on your baby's skin. They are most often caused by a viral infection or an allergic reaction to food, medication, or an insect bite. While they can look alarming, hives are usually harmless and resolve on their own, though any breathing difficulty needs immediate emergency care.
My Baby's Head Shape Looks Abnormal
Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.
Achondroplasia (Dwarfism) in Babies
Achondroplasia is the most common form of short-limbed dwarfism, affecting about 1 in 15,000 to 40,000 births. It is caused by a mutation in the FGFR3 gene and is usually apparent at birth with characteristic features including short limbs, a larger head, and a prominent forehead. Intelligence is normal. With monitoring for specific complications and supportive care, children with achondroplasia lead full, active, and independent lives.
Adenoid Hypertrophy and Breathing
Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.