But that asthma cannot be diagnosed until my son is older than 2 or even 3 years old. Why is that?
The observation that your young son is wheezing does not necessarily mean that he has asthma. Wheezing in infancy is never normal and should be reported to the pediatrician. Many children do wheeze during their first 12 months of life and only a small percentage of them ultimately develop asthma over time. The major stimulus to wheezing in the toddler years is typically a viral respiratory tract infection.
Wheezing in very young children is categorized into two general patterns: non-allergic wheezing and allergic wheezing. In the first instance, wheezing occurs when the infant becomes ill with an acute upper respiratory viral infection. The child’s airways grow larger in the preschool years, and the wheezing disappears as the toddler grows. In non-allergic wheezing, symptoms seen in infancy do not recur with subsequent upper respiratory viral infections. The “wheezy chest” is not an early manifestation of asthma.
Patterns of Wheezing in Infants and Babies
Non-Allergic Wheezing Pattern
Wheezing typically occurs in the setting of a viral upper respiratory tract infection.
Eczema, allergic rhinitis, and food allergy are not usually present.
Wheezing abates as the baby grows and reaches preschool age (ages 3–6).
The wheezing seen in infancy in these children is not a harbinger of asthma.
Allergic Wheezing Pattern
Wheezing typically occurs in the setting of a viral upper respiratory tract infection.
Maternal allergy or asthma is often present.
Eczema, allergic rhinitis, and food allergy are typically also present.
As the child grows, the pattern of wheezing when the child is ill with upper respiratory viral infections continues.
The wheezing seen in infancy in these children is likely a symptom of asthma, which potentially persists over time.
Infants who exhibit the second, allergic, pattern also wheeze when infected with an acute upper respiratory virus. However, they are more likely to have real asthma that continues throughout childhood. They are also more likely to have diagnosed allergies such as allergic rhinitis, food allergy, or eczema. Their airways will also grow larger as they become toddlers, but the wheezing persists. They have asthma, not a narrowed, immature airway as a cause of wheezing in infancy during upper respiratory viral infections.
It is difficult for doctors to be certain that a child has asthma or has allergic wheezing, before the age of 18–24 months. This is not to say that children younger than that do not develop asthma, only that it is not easy to confidently make a definitive diagnosis at that time.
For practical purposes, the diagnosis of bronchial asthma in a very young child is generally based on a recurring pat-tern of cough and/or wheeze that responds to a bronchodilator short term and that is further controlled long term with anti-inflammatory medication. A definitive diagnosis of asthma is also more likely in children under the age of 3 years if the child has experienced more than three episodes of wheezing in the prior 12 months, if the child has a confirmed diagnosis of eczema (atopic dermatitis) and/or allergic rhinitis, if there is a parental history of asthma, and if wheezing has occurred in the absence of a cold or infection.
Kerrin’s comment:
I recall being very frustrated by the fact that no one would or could diagnose my son with asthma with certainty before he was about 2 years old. Only after he had three episodes of respiratory difficulty did I hear the word asthma mentioned with conviction. As a parent, you want to know exactly what is happening with your child so that you can be educated and prepared, but without a definite diagnosis of any-thing, I constantly felt very anxious about his health. After he was finally diagnosed, we were able to educate ourselves about the condition and begin preventive treatment plans.
My son was prescribed Zyrtec [cetirizine] at the same time he was officially diagnosed with asthma. He takes it every day, along with Singulair [montelukast]. His asthma symptoms have been well controlled since he started taking these medications, and his allergies have also been manageable.