Development of asthma in children

Asthma is the most common long-lasting (chronic) disease of childhood. It usually develops before age 5.¹ Many children with allergies get asthma, but not all. And not every child with asthma has allergies.

In most cases of persistent asthma, the first symptoms (such as wheezing) start in the first years of life. One study notes that about 25% of children with persistent asthma began wheezing before 6 months of age and about 75% began wheezing by 3 years of age.²

Early infection with respiratory syncytial virus (RSV) that causes a lower respiratory infection is a risk factor for wheezing.² However, other research indicates that upper respiratory infections that do not progress to lower respiratory infections may protect a child from developing asthma.²

If your child has persistent asthma, he or she may have:

• Developed symptoms before age 3.
• Had allergies in infancy and childhood.
• A family history of allergies.
• Wheezing when there is no viral infection.
• Recurrent asthma attacks associated with viral infections.
• Wheezing severe enough to require hospitalization.

Asthma as your child grows

It is likely that your child will not develop asthma even if he or she wheezes as an infant.

• About 15% of infants who wheeze develop persistent wheezing and asthma.²
• About 60% of infants who wheeze no longer wheeze by age 6.²
• About 50% of preschool-age children who wheeze have persistent asthma later in childhood.³

It is also difficult to predict whether your child's asthma will continue into the teen years or adulthood.

• In most cases of mild intermittent asthma associated with respiratory infections (rather than allergies), symptoms tend to become less severe and may go away by the teen years. In one study, children who had mild wheezing generally did not have symptoms as adults.⁴
• Asthma seems to continue into the teen years in children who have moderate to severe asthma. If your child has moderate asthma, he or she may have moderate asthma as an adult.⁵ In one study, 75% of children diagnosed with severe asthma continued to have asthma as adults.⁴
• Asthma sometimes recurs in adulthood, especially in people who smoke.⁵

Studies indicate that although children may outgrow asthma symptoms, the inflammation and damage to the lungs continues.⁶

Citations

1. Fireman P (2001). Asthma. In RA Hoekelman, ed., Primary Pediatric Care, 4th ed, pp. 1330–1335. St. Louis: Mosby.

2. Guilbert T, Krawiec M (2003). Natural history of asthma. Pediatric Clinics of North America, 50(3): 524–538.

3. Wood RA (2002). Pediatric Asthma. JAMA, 288(6): 745–747.

4. Martinez FD (2002). Development of wheezing disorders and asthma in preschool children. Pediatrics, 109(2): 362–367.

5. Martinez FD (2001). Links between pediatric and adult asthma. Journal of Allergy and Clinical Immunology, 107(5): 449S–455S.

6. Stempel DA (2003). The pharmacologic management of childhood asthma. Pediatric Clinics of North America, 50(3): 610–629.