RESUMEN
Case report Dust is a known mixture and carrier of multiple allergens and an epidemiologic study demonstrated the presence of peanut proteins in school cafeterias and classrooms, suggesting that schools may play an important role in exposure to environmental food allergens. While inhalation of food allergens is a known trigger of IgE-mediate acute respiratory reaction as rhinitis and wheezing, little is known about persistent allergic asthma and/or rhinitis induced by chronic inhalation of food allergens. Here we report two cases of teenagers with nuts allergy presenting with persistent respiratory symptoms when exposed to closed and dusty environments. The first case concerns a 12-year-old boy allergic to walnut and hazelnut (specific IgE > 100 and 81.70 kU/l, respectively). For some years he has had a persistent mild asthma, frequent nasal occlusion and rhinorrhea, without any allergic sensitization to aeroallergens. Symptoms occurred exclusively during school period when he required maintenance therapy with inhaled and nasal steroids. He was asymptomatic and did not need any treatment during summer. During the lockdown period due to Covid-19 pandemic, he did not attend school for several months and he was able to discontinue inhaled corticosteroid therapy without recurrence of asthma and rhinitis symptoms. Asthma recurred after he returned to school, but with only mild intermittent symptoms, probably thanks to the use of masks and the frequent airing of the classrooms. On a single occasion he experienced nasal occlusion and rhinorrhea after that a parent had eaten hazelnut cream in the same room where he was. The second case deals with a 17-year-old boy with a history of several food allergies (milk, egg, wheat, banana, nuts, hazelnuts) and mild persistent asthma in absence of sensitization to aeroallergens. He successfully underwent oral desensitization for milk, egg and wheat in previous years. Asthma symptoms improved over the years together with progressive development of oral tolerance to food allergens for which oral immunotherapy had been done. On the other hand, he referred persistence of allergic rhinitis especially during the school year and his symptoms got worse in classroom. Exhaled nitric oxide was quite increased with evidence of eosinophils in nasal smears. In-vitro and in-vivo tests only detected food allergens sensitizations, in particolar to walnuts and hazelnuts (specific IgE were 61.00 and 55.50 kU/l respectively). These two clinical cases suggest that food allergens might be causative agents of allergic persistent asthma and/or rhinitis as aeroallergens do.