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Aim: To evaluate the association between reported symptoms upon exposure to airborne allergens and sensitization to the corresponding allergen.

Method: In a population-based cohort, 1647 children aged 12 years were interviewed about symptoms from eyes, nose and lower airways upon exposure to birch, timothy, cat, dog, and horse, and were afterwards skin prick tested for the same allergens. Positive predictive value (PPV) was calculated for reported symptoms in relation to sensitization.

Results: The prevalence of sensitization was generally higher in boys than girls, while reporting of symptoms was equal upon exposure. The proportion of sensitization among individuals reporting symptoms ranged from 70% to 95% and was highest for lower airway symptoms upon dog and cat exposure. Lower airway symptoms were the least prevalent but had the highest PPV for sensitization to each allergen (PPV = 75%–95%). The increasing number of symptoms when exposed to a specific allergen increased the likelihood of sensitization, and the PPV for three symptoms upon cat and dog exposure was > 95%.

Conclusions: Self-reported symptoms upon aeroallergen exposure highly predict sensitization to the same allergen. Unless allergen-immunotherapy is indicated, objective measurements of sensitization may not always be necessary in 12-year-old children with a convincing history of airborne allergy.