Fig. 3

Mean Total Nasal Symptom Score (TNSS). HDM-allergic participants experienced an increase of nasal symptoms beginning from baseline (t = 0). Allergics exposed to a modest HDM target experienced a plateau in symptoms around 1.5 h following the onset of allergen exposure. Allergic participants exposed to a higher HDM target experienced a significantly greater peak in mean TNSS at 2.5 (p < 0.05) and 3 h (p < 0.01) compared to modest target allergics. Comparisons between modest target allergics and non-allergics are represented by “†”, high target allergics and non-allergics by “‡” and modest and high target allergics by “*”. †/‡/* = p < 0.05, ††/‡‡/** = p < 0.01, †††/‡‡‡/*** = p < 0.001, ††††/‡‡‡‡/**** = p < 0.0001