In A Nutshell – Birch Co-sensitization Among Children With Peanut, Hazelnut And Almond Allergies.

Abstract

Individuals diagnosed with nut allergies often experience mild oropharyngeal symptoms only, referred to as pollen food allergy syndrome (PFS) secondary to cross-reacting homologous proteins in pollens and nuts. We investigated the association between peanut, almond and hazelnut allergies, and birch co-sensitization to provide insight into the prevalence of PFS among nut allergic children seen in our practice. After IRB approval, we performed a retrospective chart review of 67 pediatric patients seen in our clinic with a diagnosis of peanut, almond or hazelnut allergy and investigated the presence of birch co-sensitization. Of 67 patients, 58 had peanut allergy, 48 had hazelnut allergy and 45 had almond allergy. Hazelnut and almond co-sensitization was seen in 41(61%) patients while peanut, hazelnut and almond co-sensitization was seen in 35 (52%) patients. Birch sensitization was present in 41 (61%) patients, while 10 (15%) patients had not been tested. Of 58 peanut allergic patients, 35 (60%) were birch sensitized; 9 (16%) had not been tested (95% CI, 47.7-72.9%). Of 48 patients with hazelnut allergy, 35 (73%) had birch sensitization, and 5 (10%) had not been tested (95% CI, 60.3-85.4%). Birch sensitization was seen in 33 (76%) of 45 almond allergic patients, while 6 (13%) had not been tested (95% CI, 60.4-86.2%). Here we present preliminary data suggesting the presence of birch co-sensitization among a proportion of patients with peanut, hazelnut and almond allergies, raising the possibility of PFS. This may have implications in failed oral challenges, with PFS being a potential confounding factor.