Temporal Patterns of Allergen Sensitisation in the General Population: The LEAD Study

Background Allergic sensitisation is traditionally viewed as a stable trait despite studies suggesting that it may vary across life‐course. This study aims to provide longitudinal evidence of allergic sensitisation and its associated factors in the general population. Methods Aeroallergen sensitisation was assessed in the Austrian population‐based cohort using repeated skin prick testing (SPT) across 3 visits (mean visit interval, 4.25 ± 0.33 years). Longitudinal sensitisation patterns were characterised as stable nonsensitised, stable sensitised, new‐onset, resolution or fluctuating. We examined demographic, metabolic, behavioural, environmental and immunological factors across age strata (< 18, 18 ≤ 40, 40 ≤ and ≥ 60 years). Results Among 5046 individuals with follow‐up and valid SPT in all 3 visits, 54.4% remained stably nonsensitised and 30.6% stably sensitised, 5.6% experienced resolution, 4.8% new onset and 4.6% fluctuating sensitisation. New onset expectedly predominated in < 18 years, fluctuation in 18 ≤ 60 years and resolution in ≥ 60 years, indicating that sensitisation is modifiable and time‐varying. Stable sensitisation was strongly associated with parental allergy and blood eosinophils while cumulative smoking modestly reduced its likelihood. Fluctuation was linked to adiposity (in adults ≥ 40 years old) and environmental exposures. Aeroallergen‐specific analysis showed new‐onset sensitisation was driven by outdoor allergens (ragweed, tree pollens and pets) whereas fluctuation was driven by seasonal pollens. Conclusion Although predominantly stable, allergic sensitisation is dynamic and exhibits substantial temporal variation. Resolution and fluctuation occur across all ages and new sensitisation can emerge well into adulthood. These findings challenge the traditional view of fixed sensitisation and suggest it reflects a modifiable phenotype shaped by age and environmental and lifestyle exposures.