Children with allergic sensitization more likely to have asthma, rhinitis as young adults

Most individuals with onset of allergic sensitization when aged 8 years or younger developed asthma or rhinitis before young adulthood, according to data published in The Journal of Allergy and Clinical Immunology: In Practice.

“Longitudinal studies have demonstrated that aeroallergen sensitization in childhood is strongly associated with the development of asthma and rhinitis during childhood and teenage [years],” Joakim Bunne, MD, of Umeå University in Sweden, and colleagues wrote. “Preschool sensitization is also a risk factor for asthma persistence during adolescence.”

According to the researchers, the prevalence of allergic sensitization increases with age, peaking in young adulthood with rates to airborne allergens reaching up to 50% depending on population and area.

“The high prevalence of sensitization in young adulthood is a result of high incidence and low remission during childhood and adolescence,” they wrote.

To evaluate the impact of age at onset of sensitization to airborne allergens on the development of asthma and rhinitis during childhood and adolescence, the researchers reviewed data on 1,510 children who participated in skin prick tests and a questionnaire about allergic diseases at median ages of 8, 12 and 19 years.

Of those included in the study, 323 developed sensitization at age 8 years or younger, 160 between 8 and 12 years, and 184 between 12 and 19 years; 843 were never sensitized.

The prevalence of selected outcomes was highest at age 19 years, including current wheeze (15.4%), asthma (10.9%), symptoms of rhinitis (28.3%) and rhinitis (13.4%).

Additionally, the prevalence of any positive SPT increased by age, from 21.4% at 8 years, 31.1% at 12 years and 43% at 19 years, with a similar pattern for sensitization to any animal and any pollen.

The association between age at onset of sensitization and asthma and rhinitis remained at age 19 years after adjusting for covariates. In general, allergic sensitization at age 8 years or younger showed a stronger association with rhinitis (risk ratio [RR] = 22.3; 95% CI, 13.3-37.6) than asthma (RR = 4.68; 95% CI, 3.15-6.97) at age 19 years.

Rhinitis at age 19 years also was strongly associated with sensitizations at 8 years or younger to any pollen (RR = 20.5; 95% CI, 13.3-31.6) or animal (RR = 12.1; 95% CI, 8.15-18) compared with those never sensitized to any pollen or animal. Researchers observed similar findings for sensitization to any pollen or animal and asthma outcomes.

Finally, Bunne and colleagues noted that sensitization to aeroallergens was more common among boys than girls at all three study time points.

“Despite this, reported symptoms of asthma and rhinitis were more common among girls than boys at 19 years of age,” they wrote.

The researchers concluded that early sensitization was associated with an “allergy cluster” defined by early sensitization, multi-sensitization, higher levels of sensitization and a high risk for allergic disease, independent of the presence of allergic diseases in the children’s parents.