Alpha-Hairpinin (Pap s 1.0101) Sensitization and Optimized Prick-to-Prick Testing Define Clinical Poppy Seed Allergy...

Poppy seed (Papaver somniferum) allergy is an uncommon but potentially severe form of seed hypersensitivity. Despite the increasing consumption of seeds worldwide, data on poppy seed (PS) allergy remain limited, mostly derived from case reports.

This study aimed to describe the clinical and laboratory characteristics of PS-allergic children and evaluate the diagnostic performance of conventional and molecular assays.

A retrospective review was conducted on children evaluated for suspected PS allergy at a tertiary pediatric allergy center between 2020 and 2024. Clinical reactivity was confirmed by an oral food challenge or a consistent reaction history with documented sensitization. Diagnostic tools included prick-to-prick (PtP) testing, serum specific IgE (sIgE), and multiplex microarray Allergy Xplorer (ALEX²) for PS allergens, including α-hairpinin.

Of 191 PS-sensitized patients, 38 (19.9%) were clinically allergic. Anaphylaxis occurred in 10 cases (26.3%). Median PtP wheal size, PS-sIgE, and α-hairpinin levels were significantly higher in allergic patients than in tolerant ones (8.0 mm vs 3.0 mm, P < .001; 3.62 vs 0.79 kU/L, P = .001; and 7.20 vs 0.00 kUA/L, P < .001, respectively). PtP wheal size and α-hairpinin levels showed the best diagnostic performance (area under the curve [AUC] = 0.937, positive likelihood ratio [LR+] = 4.86 and AUC = 0.932, LR+ = 5.88, both P < .001). Many children had multiple food allergies, most commonly to sesame and tree nuts.

Although rare, PS allergy can induce severe reactions and should be considered in children with multiple seed or nut allergies. PtP and α-hairpinin testing demonstrated strong diagnostic performance, with α-hairpinin emerging as a promising molecular marker for distinguishing true PS allergy from cross-reactivity.