D3.96 - High burden of latent aeroallergen sensitization in healthy urban medical students: a blinded skin prick test study from South India

Aeroallergen sensitization may precede clinical allergic disease, yet its prevalence and clinical relevance in apparently healthy young adults remain poorly characterized. We investigated sensitization patterns and clinical correlates using blinded skin prick testing (SPT) in an urban medical student cohort.

In a prospective observational study, 110 undergraduate medical students were recruited irrespective of allergy history. Blinded SPT was performed using 12 common aeroallergens with saline and histamine controls. Valid responses were defined by standard control criteria. After exclusions for invalid tests or basal hyperreactivity, 97 participants were analyzed. Sensitization patterns, co-sensitization profiles, symptom questionnaires, family history, and wheal morphology (erythema and pseudopods) were evaluated.

Sensitization to ≥1 allergen occurred in 63/97 participants (64.9%), while 34 (35.1%) were non-sensitized. Polysensitization predominated, with tetra-sensitization most frequent (23.8%). Indoor allergens were dominant: Dermatophagoides farinae (66.7%), D. pteronyssinus (63.5%), and cockroach (61.9%). Dual mite sensitization was associated with higher symptom burden and polysensitization (OR≈3.0, p<0.05), while cockroach sensitization correlated with D. pteronyssinus co-sensitization (OR=2.7, p=0.04). Weed pollens showed predominantly polysensitized profiles, whereas fungal allergens produced mild or latent sensitization.

Pseudopods were observed in 44/63 sensitized subjects (69.8%) and were strongly associated with polysensitization ≥4 allergens (OR 3.8, p<0.001), persistent rhinitis (OR 2.9, p<0.01), exercise-induced symptoms (OR 2.3, p=0.03), and family history of atopy (OR 2.6, p=0.01). Fungal allergens produced erythema without pseudopod formation. No systemic reactions occurred.

Latent aeroallergen sensitization is common in healthy young adults and predominantly driven by indoor allergens. Pseudopod morphology during SPT identifies a higher-risk atopic phenotype and may represent a simple qualitative marker for early allergy risk stratification.