This longitudinal, population-based cohort study (LEAD, Austria) followed 5,046 individuals aged 6–82 at baseline across 3 visits (mean interval ~4.25 years) to characterise temporal patterns of aeroallergen sensitisation by repeated skin prick testing (SPT), and identify associated demographic, metabolic, behavioural, environmental, and immunological factors by age stratum.
54.4% were stably nonsensitised and 30.6% stably sensitised; 5.6% had resolution, 4.8% new-onset, and 4.6% fluctuating sensitisation. New-onset predominated in those <18 years (8.9%), fluctuation peaked in the 40–60 age group (8.3%), and resolution was highest in those ≥60 years. Stable sensitisation was strongly linked to parental allergy and blood eosinophils (OR 3.00 [95% CI 2.25–4.00] for parental allergy in 18–40 year-olds), while cumulative smoking modestly reduced its likelihood (OR 0.99 per pack-year). Fluctuation was associated with adiposity and environmental exposures (PM10, NO2, proximity to main roads).
- SPT only (no allergen-specific IgE for all participants), so sensitisation intensity and mechanism cannot be fully assessed. - Cohort is Austrian/European, limiting generalisability to other genetic backgrounds or allergen environments. - Key drivers of fluctuation (hormonal changes, detailed diet, illness history, granular pollutant data) were not fully captured; quantitative wheal size data were unavailable, making it hard to separate borderline from clear positives in the fluctuation group.
Allergic sensitisation is not fixed — clinicians should consider repeat SPT over time, especially in older adults (where resolution is common) and in those with fluctuating or seasonal symptoms, as single cross-sectional testing may miss dynamic changes. New sensitisation to outdoor allergens (ragweed, tree pollen, pets) can emerge in adulthood, so a negative historical test does not rule out current sensitisation.
