Signs of Bronchiolitis in Babies
The short answer
Bronchiolitis is a common lower respiratory infection in babies under 2 years, most often caused by RSV. It typically starts like a cold with runny nose and cough, then progresses to wheezing and breathing difficulty over 2-3 days. Most cases are mild and resolve at home within 1-2 weeks, but young infants (under 3 months) and babies born prematurely are at higher risk for severe illness requiring hospitalization.
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By Age
What to expect by age
0-3 months
Young infants are at the highest risk for severe bronchiolitis. Their small airways are particularly vulnerable to swelling and mucus buildup. Warning signs include fast breathing (over 60 breaths per minute), nasal flaring, chest retractions (ribs visible with each breath), poor feeding, and pauses in breathing (apnea). Any infant under 3 months with breathing difficulty from bronchiolitis should be evaluated urgently, as hospitalization may be needed for oxygen support or IV fluids.
3-12 months
Bronchiolitis in this age group often begins with 2-3 days of cold symptoms before progressing to wheezing and increased breathing effort. The illness typically peaks around days 3-5 and then gradually improves over 1-2 weeks, though cough may linger longer. Home care includes nasal suctioning, humidified air, frequent small feedings, and monitoring breathing. There is no medication that shortens bronchiolitis -- antibiotics do not help since it is viral.
12-24 months
Toddlers generally handle bronchiolitis better than younger babies because their airways are larger. Symptoms may include persistent cough, wheezing, and mild breathing difficulty. Most can be managed at home with supportive care. However, if your toddler is breathing rapidly, refusing fluids, or has not had a wet diaper in 6-8 hours, medical evaluation is needed. Children with asthma, heart conditions, or immune deficiencies are at higher risk for complications.
What Should You Do?
When to take action
- Your baby has a runny nose and cough but is breathing comfortably and feeding reasonably well.
- Your baby has mild wheezing after the peak of illness but is improving day by day.
- Your baby's breathing rate is normal when calm (under 40-60 breaths per minute depending on age).
- Your baby under 6 months develops any wheezing or increased breathing effort.
- Your baby is feeding less than half of normal amounts.
- Your baby's cough is worsening after day 5 of illness or symptoms have lasted more than 2 weeks.
- Your baby is breathing very fast (over 60 breaths per minute), has chest retractions, or nasal flaring.
- Your baby's lips, tongue, or fingernails turn blue or dusky.
- Your baby has pauses in breathing, is extremely lethargic, or cannot be roused for feeds.
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
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Related Medical Concerns
RSV in Babies: What to Know
RSV (respiratory syncytial virus) is a common virus that affects nearly all children by age 2. Most babies have mild cold-like symptoms, but some, especially young infants and those with underlying conditions, can develop breathing difficulties. Watch for fast breathing, flaring nostrils, or visible chest pulling - these are signs to seek medical care.
Baby Wheezing
Wheezing is a high-pitched whistling sound heard during breathing out, caused by narrowed airways. In babies, the most common cause is a viral infection like bronchiolitis (often RSV). Many babies wheeze once or twice during their first viral illnesses and never wheeze again. However, wheezing with breathing difficulty always warrants medical evaluation.
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Achondroplasia (Dwarfism) in Babies
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