The wheezing baby – how should asthma in infancy be managed?

How common is it to encounter this condition at the pediatric clinic?

The answer is simple, very common.
One of the most common symptomatology seen in infancy, that causes parents to visit their pediatrician is cough and shortness of breath with wheezing. In fact, about 50% of infants under the age of 2-3 years experience at least one episode of wheezing. Recurrent episodes (defined as more than 3 in the span of 6 months) are also relatively common and occur in about 15% of children.

What is wheezing?

The reason that infants’ lungs tend to wheeze is firstly the result of the small diameter of their airways. When the airways are small – any slight obstruction, even if it is partial, for example as a result of phlegm that may accumulate, can cause wheezing (imagine a flow of air in an instrument and the change in notes that one hears depending on the instrument’s diameter). An obstruction of the airways can occur as a result of simple and benign conditions, such as viral infections, but can also be the result of other significant causes that should be detected immediately and managed appropriately in order to avoid complications.

What causes wheezing in children?

The most common cause for wheezing in children is an infection in the respiratory tract, and in most cases it is the result of a viral infection, that penetrates the cells of the tract and cause localized inflammation mediated by the immune system.
Many respiratory viruses have a predisposition (or a tendency) to attack the airways, including influenza, RSV, COVID-19, rhinovirus, adenovirus, and many others. Most of the time, the viral infections do not have a specific therapy, other than exceptional cases, and the treatment is a supportive one that prevents respiratory exacerbations.
Less commonly, bacterial respiratory infections can also present with wheezing, and these will have specific antibiotic therapies – therefore it is important to undergo examination by a physician in case of significant worsening or lack of improvement, so that the physician can detect the type of infection and treat it adequately. Keep in mind, though, that these infections are less common than the typical viral infections, and in most cases there is no need for antibiotics when a child presents with wheezing.

What else can cause wheezing and should not be missed?

An additional cause for wheezing in infancy is aspiration of a foreign body into the lungs. Most of the time this happens in babies that are previously healthy but were seen to choke on a piece of food or object that they put into their mouth, and if the object passes the vocal cords and enters the airways – it can cause a partial or full obstruction of the bronchus and could even cause a local inflammation, and manifest with cough and wheezing.
It is important for parents to be aware of the dangers of aspiration – which can cause severe respiratory infection and even death, depending on where the object gets stuck. It is important to avoid foods such as nuts, sausages, grapes, or foods that do not dissolve in the secretions of the mouth and can be accidently aspirated and get stuck in the airways. If an episode of choking is suspected, the child must be assessed by a physician as soon as possible and the healthcare team must be made aware of the suspicion. In most cases, when wheezing is the result of aspiration of foreign object, their history will be positive for an episode of choking, there will not be fever or a runny nose, and the wheezing will be typically heard over one area more than other areas of the lung. Wheezing that is caused by viral infections can be heard diffusely across the lungs. Find out more about safe foods in babies and children in the link here.
There are additional causes for wheezing in children, that are a lot less frequent, and the physician will be able to detect these depending on the clinical history and their physical examination. These include congenital defects in the vasculature or the respiratory tract, that can cause a secondary narrowing of the trachea or the tract due to external pressure, congenital heart defects that may cause respiratory congestion or heart failure, lymph nodes or cancerous tumors that may press on the respiratory tract, abnormal structures of the connective tissue with the formation of soft cartilage in the trachea or bronchi or narrowing as a result of surgery or prolonged intubation, and also episodes of recurrent aspiration of gastric contents or saliva into the respiratory tract – such as in children with neurologic injuries or those who have dysfunctional swallowing. In order to detect these complex situations, a pulmonologist should be consulted, so that they can gradually rule out the problematic causes. Of course, these situations usually occur in children who have underlying conditions and have not been growing or developing well, and that is why they visit the hospital for full investigations and work-ups.

What is the difference between a wheezing baby (asthma in infancy) and asthma, and what are the chances that a wheezing baby will develop asthma?

Real asthma (find out more about it here) is a chronic inflammatory condition that manifests with recurrent episodes of cough, wheezing and shortness of breath.
It is a condition that combines genetic tendency and specific reaction of the inflammatory cells in the body to environmental triggers. About 80-90% of the children under the age of 3 who present with recurrent episodes of wheezing will not go on to develop asthma when they grow older.
Nonetheless, one can try and estimate which of the children will end up having real asthma or persistent asthma, with the help of several risk factors, which when present, increase the risk of this happening. Risk factors include a parent with asthma, asthma of the skin (atopic dermatitis), or allergies to different allergens (for example, dust mites, olive tree pollen, cat hair, etc.), allergy to different foods (peanuts or milk), eosinophilia of the blood (increase in number of cells responsible for the allergic reaction in the body) and episodes of wheezing in children that occur without any clear triggers of febrile viral illness.
An additional risk factor that significantly increases the risk of asthma is exposure to cigarette smoking. And that is why it is important to tell the parents that they must stop smoking, or at least stop smoking during pregnancy and afterwards avoid smoking around the child.
The final and objective diagnosis of asthma is done around the age of 4-6, when the children are able to cooperate and carry out pulmonary function tests. Under the age of 3, the diagnosis is made with the help of clinical history and physical examination, and that is why prior to confirming this diagnosis, it is important to consult with a pulmonologist.
Often, wheezing children are defined as having “asthma of infancy”. And then we often tell families that this is typically a transient condition, that resolves with tie…

How is wheezing managed in infants?

Obviously, the management depends on the cause of the wheezing. When there is a clear cause that can be treated, then treatment is offered accordingly. However, in most cases, the cause is a viral infection, that does not have a specific treatment. Most of the time there is no need for treatment and it is better not to offer unnecessary treatment, such as antibiotic treatment.
What about treating with nebulization or inhalers? The answer is that most of the children who experience wheezing episodes will not have asthma in the future, some will response to “anti-asthma” therapy, and therefore treating them with nebulizers or inhalers is worth a try.

Keep in mind that there is a difference between a 1-year-old that has already been to the doctor 3 times in the past 3 months and has had wheezing on auscultation every time, especially if they carry risk factors for developing asthma in the future, and a 1 year old child who is previously completely healthy, that is visiting the doctor with an episode of wheezing for the first time. It makes sense to treat the first child with “anti-asthma” therapy (even though they do not have asthma) and to watch and wait with the second child, knowing that therapy is probably unnecessary and ineffective.

What is the purpose of treating children with nebulizers or inhalers?

The purpose of these is to dilate the airways and reduce the active inflammation, as well as to improve the cleansing of the respiratory tracts by effectively expelling the phlegm from the tract. Therefore, in most cases there are two types of products that can be used – bronchodilators – such as Ventolin and inhaled steroids – such as budicort or flexotide.
Similarly to what is mentioned in the chapter about nebulizers vs inhalers, the use of inhalers with a spacer carried an advantage of nebulizers, both in terms of length of time of treatment and the penetrance of the small molecules into the small airways. Do not forget to mix the inhaler before every puff, so that the active ingredient mixes well with the preservative in the inhaler.

And now that we have mentioned this, when do we prefer administering nebulizers? We prefer these in several situations – when there are excessive secretions and the use of saline nebulizers are helpful in softening the secretions and expelling them (sometimes we recommend the use of concentrated or hypertonic 3% saline, vs 0.9%). The second reason for giving nebulization is when the impression is that of an upper obstruction, such as stridor, and then there is no issue with the small molecules having to reach the small airways. The third reason is when the child or parents are not as cooperative with the use of inhalers – some children prefer nebulizers, it calms then down and parents could swear that they are more effective. In such situations there is no reason to insist on the use of inhalers.

Will a wheezing child necessarily respond to therapy?

Keep in mind that many children, and especially younger babies that do not have a tendency for asthma or other risk factors for asthma, will simply not respond to “anti-asthmatic” medications or inhalations, and then there is no point in administering this therapy. In other words – it is worthwhile trying the therapies and assessing whether they were effective. If they are ineffective, there is not reason to continue using them as these therapies can also have side effects.
However, in young children that have frequent episodes and respond well to the therapies every time, sometimes it is worthwhile considering preventive treatment, even between the episodes, just like we do in older children who are diagnosed with asthma. Regular treatment with steroidal inhalers can reduce the chronic inflammatory process in the respiratory tract and prevent recurrent episodes when the child is frequently exposed to different triggers. Once again, keep in mind that there is no point in administering inhalers directly into the mouth, without the use of a spacer (aero-chamber) in young children, as there is no way that they will be able to take in the products adequately without the use of a mediating device. If the child does not improve, consult with a pediatric pulmonologist for a full assessment.

In summary, this is a very important topic in pediatrics. I hope I was able to clear things up, and most important, may you always be healthy and safe!