What should you know about allergic bronchiolitis?

Bronchiolitis usually describes inflammation of the smallest airways during a viral infection, particularly in babies and young children. Allergy can trigger cough or wheezing, but those symptoms may point to a different airway problem rather than typical bronchiolitis.

A child with bronchiolitis may develop a runny nose, cough, noisy or fast breathing, feeding difficulty, and sometimes fever. Wheezing can occur when narrowed small airways make breathing out harder.

When someone uses the word “allergic,” they may be describing wheeze after exposure to dust, pollen, pets, smoke, perfume, or another irritant. Repeated episodes, symptoms between infections, eczema, or a family history of allergic disease may lead the clinician to consider asthma or another cause. The name alone cannot establish the diagnosis.

Arrange a child health assessment if this is a first episode of wheezing, the diagnosis is uncertain, symptoms keep returning, or feeding and sleep are affected. Note when symptoms began, whether there was a cold or fever, possible triggers, previous episodes, and any medicines already given.

Offer small, frequent feeds and keep the child away from tobacco smoke, vaping aerosols, incense, and strong fragrances. Saline nose drops may make feeding easier when the nose is blocked. Do not give antibiotics, cough remedies, antihistamines, inhalers, or nebulised medicine unless a clinician recommends them for that child. A nebuliser is not automatically needed for typical bronchiolitis.

Seek urgent medical care if breathing becomes faster or harder, the skin pulls in between or beneath the ribs, the nostrils flare, grunting develops, or the child is too breathless to feed. Blue or grey lips, pauses in breathing, marked drowsiness, limpness, or difficulty waking require emergency help.

Prompt assessment is also needed when the child drinks much less than usual, has noticeably fewer wet nappies, repeatedly vomits feeds, or is getting worse. A very young baby, a child born prematurely, or a child with heart, lung, immune, or neurological problems should be assessed early when breathing symptoms appear.

Ask what diagnosis best explains the breathing sounds, whether the pattern fits viral bronchiolitis or recurrent wheeze, and which changes should trigger reassessment. It is also useful to ask whether any suspected trigger should be avoided, whether an inhaled medicine is appropriate, how it should be given, and when follow-up is needed.