Introduction

You’ll expect your infant to laugh, talk in their baby language, and even cry, but if you’re hearing a different sound coming out of them, you might be confused or even alarmed. Although it can be worrying, some sounds might be completely harmless.  

It’s essential to recognise the distinction between different sounds that may sound similar but occur for distinct reasons. A doctor will check your baby and identify the cause of the noise. 

This article will cover some causes of noisy breathing in infants, but remember, you should never diagnose your infant yourself.

What is noisy breathing in infants?

Noisy breathing can be defined with different terms:¹

• Stridor - a high-pitched sound, often heard through inhalation and exhalation (breathing in and out) that occurs because something is blocking the voice box in your throat
• Wheezing - This is a high-pitched noise that occurs specifically when you breathe out. The reason for wheezing is often because of narrowing, spasming or blockage of the airways in the lungs
• Stertor - A noise that is formed in the nose or back of the throat. It has a deeper pitch, similar to that of snoring

 Therefore, the type of noise can help to determine what part of the airway is affected.

If your infant's breathing changes suddenly, it could be due to a number of different reasons, which we mention below.

Overview of laryngomalacia

Laryngomalacia (pronounced Lar-in-go-mal-asia) is one of the most common reasons why infants have stridor. It affects growth and development, and can give an indication of something being wrong in the airways, which is why it should be diagnosed as early as possible.

Key characteristics include it being worse when the infant is feeding or lying flat on their back.² A doctor will want to check the mouth, nose, throat and probably chest of your infant before laryngomalacia can be confirmed.²

It is common for babies to be born with it, with over 50% of newborns having it during their first week of life, and even more in the first 4 weeks of their life.⁶

Possible causes of laryngomalacia

The reason why laryngomalacia occurs has been linked to the cartilage (soft tissue) around the voice box not being fully formed yet, and incorrectly falling inwards when the infant breathes in, resulting in the stridorous sound.²

Another possible cause for the stridor noise is due to the nerves around the voice box not sending or receiving signals correctly.²

Furthermore, if the infant is smaller and has less muscle, likely, there is also less muscle around their airways, making it harder for them to breathe in.²

Acid reflux can potentially worsen laryngomalacia by irritating the throat; however, it is not a cause of it.² 

Management

Laryngomalacia has treatment based on what symptoms the infant is experiencing and how they are coping²

Mild symptoms - waiting to see if their breathing gets better on its own without intervening. By the time they are 18 months old, their symptoms may have resolved.

Severe symptoms - affecting up to 20% of infants; it includes the infant struggling to breathe and not getting better on their own, or failing to reach developmental milestones. In this case, surgery may be necessary. The surgery would be conducted by a specialist in a hospital, and is usually well tolerated.²

Other common causes of noisy breathing in infants

Tracheomalacia

This is when the cartilage in your windpipe becomes weak, falling inwards, resulting in high-pitched breathing. It can also result in trapped mucus in your lungs.

Symptoms which differ from laryngomalacia include:³

• Choking
• Skin turns blue
• Difficulty swallowing
• Wheezing
• Constant chest infections, such as pneumonia

Bronchiolitis

An infection caused by a virus can affect the lungs of young children; it usually goes away on its own within 14 days, but may occasionally require oxygen to help manage symptoms. Staying hydrated helps to speed up recovery.

Symptoms which differ from laryngomalacia include:

• Starting with a fever, runny nose or cough, before escalating to wheezing
• Changes in lung sounds are heard when a doctor listens to your infant's chest⁴

Croup (Laryngotracheobronchitis)

Croup is the most common cause of stridor in infants and toddlers,⁵ and usually starts after a viral infection. This is an infection of the airways, particularly around the voice box and windpipe.

Symptoms which differ from laryngomalacia include:⁷

• Starting with a fever, runny nose or cough before other symptoms start
• A barking cough
• Hoarse voice
• Difficulty breathing
• Stridor when inhaling
• Being worse at night

Vocal cord paralysis

This can be one-sided (unilateral) or affect both sides (bilateral) of the voice box. This usually happens after an operation around the throat; however, some babies can be born with it as well. If it is one-sided, typical symptoms include a hoarse cry and difficulty feeding. If it is bilateral, the stridor sound can be heard, and a procedure may be required to help with their breathing. This can be diagnosed with mirrors, lights or cameras using a procedure called laryngoscopy, which simply means checking the larynx (i.e voice box).²

Symptoms which differ from laryngomalacia include:^{7, 8}

• Hoarse voice
• Change in the volume of voice
• Change in pitch of voice

Subglottic stenosis

This is when the windpipe is narrowed; babies can be born with this, but it can also be caused by tubes used for breathing or feeding being used for a long duration of time. Symptoms include

Symptoms which differ from laryngomalacia include:

• Being unaffected by the baby’s position
• Whistling noise when inhaling
• Shortness of breath
• Constant episodes of croup⁹

Foreign body aspiration

If the infant suddenly finds it difficult to breathe, possibly because they have swallowed something they shouldn’t have, or mis-swallowed food, it can cause them to choke and cough.²

The hospital may suggest a scan to see where in their airways the item is lodged and to try to safely remove it.

Symptoms which differ from laryngomalacia include:

• May have a few weeks of coughing or wheezing before presenting for help
• Constant shortness of breath and difficulty breathing
• Children may complain of pain in their chest
• More likely in male infants than female
• Complete blockage of an airway can lead to pneumonia¹⁰

Key differences: laryngomalacia vs other causes

• How it starts: Gradual (laryngomalacia) vs sudden/acute (e.g., croup, foreign body aspiration)
• Stridor Type: Worse when inhaling in laryngomalacia vs can be worse when breathing out, or equally bad in other conditions
• Associated Symptoms: Feeding issues or other signs of illness (e.g., fever in croup)
• Response to Positioning: Lying flat on their back can worsen laryngomalacia
• Diagnosis: Based on history taking, assessments and investigation, eg, laryngoscopy vs bronchoscopy vs scans

When to refer or seek urgent care

Always trust your instincts when it comes to your infant’s health. If they have any of the following symptoms, call 999 for an ambulance:

• Breathing is inconsistent with long breaks in between (apnea)
• The skin has changed colour, in particular, a blue tint may be seen on the skin or lips
• Difficulty swallowing
• Poor growth or a lack of increase in weight

Summary of important points

• As your infant gets older, there is a high probability that the laryngomalacia will get better on its own and go away
• The doctor might use a procedure called laryngoscopy to view the voice box
• Surgery is only used for severe cases of laryngomalacia, such as if they are struggling to breathe or not developing as they should
• Symptoms of laryngomalacia overlap with other conditions, but diagnosis can be confirmed by laryngoscopy
• Most cases are not severe, but don’t hesitate to seek medical help
• If your infant ever has difficulty breathing, has swallowed a foreign object or is making a new or unfamiliar sound, seek medical attention immediately
• Monitor symptoms and seek appropriate care as necessary