Allergy

Early indoor aeroallergen exposure is not associated with development of sensitisation or allergic rhinitis in high-risk children

Schoos A-MM, Chawes BL, Jelding-Dannemand E, Elfman LB, Bisgaard H. Allergy 2016; 71(5): 684–691

Early allergen exposure is not associated with development of allergic disease later in childhood

Global sensitisation patterns support an association between allergen exposure and the development of sensitisation. 1However, there is a lack of evidence to validate a direct association. 1

In a study published in Allergy, Schoos and colleagues investigated the association between perinatal allergen exposure and the development of rhinitis or sensitisation to these allergens later in childhood in a cohort of children at high risk of allergic disease. 1

Study measures

This longitudinal study involved 399 high-risk children from the Copenhagen Prospective Study on Asthma in Childhood2000 birth cohort. 1Exposure to dogs and cats during pregnancy and early life were assessed through parent interviews at 1-month and 1-year clinic visits.1 In addition, dog, cat and dust mite (D. pteronyssinus and D. farinae) aeroallergen levels were assessed in dust samples taken from the child’s bed at 1 year of age. 1 

Sensitisation to these allergens was assessed by skin prick tests and immunoglobulin E measurements conducted at ½, 1½, 4, 6 and 13 years of age.1 Physician-diagnosed allergic rhinitis or eczema was recorded at 7 and 13 years of age. 1

General outcomes

At 7 or 13 years of age, one-third of children developed sensitisation (33%; n=130/399) and 21% developed allergic rhinitis (n=84/396) to any of the four allergens tested. 1

Allergen exposure in early life and sensitisation

There was no evidence of an association between sensitisation during childhood and exposure to dogs or cats in the third trimester of pregnancy (odds ratio [OR] 0.91, 95% confidence interval [CI] 0.37–2.27 and OR 0.71, 95% CI 0.31–1.64, respectively) or the first year of life (OR 1.21, 95% CI 0.53–2.74 and OR 0.75, 95% CI 0.34–1.68, respectively). 1

The levels of cat, dog and dust mite aeroallergens in bed dust samples taken at 1 year of age was not associated with sensitisation to these allergens in later childhood. 1

Allergen exposure in early life and allergic rhinitis

Allergic rhinitis at 7 and 13 years of age was not associated with exposure to dog or cat either perinatally or in the first year of life. 1

The authors did not find an association between the level of the four aeroallergens in bed dust samples and the development of allergic rhinitis. 1However, there was a borderline significant protective effect of the level of dust mite aeroallergens in the bed dust against allergic rhinitis at age 13 years (OR 0.89, 95% CI 0.79–1.00; p=0.05). 1

Conclusions

Overall, results from this high-risk cohort indicate that there is no association between early life exposure to dogs and cats and the development of allergic rhinitis or sensitisation to these animals in childhood. 1In addition, there was no association between the development of allergic sensitisation and the levels of dog, cat and dust mite aeroallergens in bed dust samples at 1 year of age. 1

However, the authors acknowledged that expsure to dogs and cats outside the home could also be important. 1

The authors conclude that their study provides no evidence to support allergen avoidance to dogs, cats and dust mites as a means to prevent the development of sensitisation or allergic disease in childhood. 1 Other environmental adjuvants may be involved in complex interactions resulting in sensitisation. 1

Report on: Early indoor aeroallergen exposure is not associated with development of sensitization or allergic rhinitis in high-risk children. Schoos A-MM, Chawes BL, Jelding-Dannemand E, Elfman LB, Bisgaard H. Allergy 2016; 71(5): 684–691.

Reference list

1. Schoos AM, Chawes BL, Jelding-Dannemand E, Elfman LB, Bisgaard H. Early indoor aeroallergen exposure is not associated with development of sensitization or allergic rhinitis in high-risk children. Allergy 2016; 71(5): 684–691.