Cockroach sensitization and its hidden links to mite and food allergens

Cockroach allergy is a common trigger of allergic reactions and may be a cause or a result of cross-reactions with other allergens. The aim of this study was to assess the pattern of sensitization to arthropod allergens in perennial allergic rhinitis (PAR) patients with positive skin prick test to cockroach. A group of PAR patients with positive skin prick test (SPT) result with cockroach extract (Blattella germanica) was selected. In addition to SPTs for other inhalant allergens, such as house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae), birch, grass, mugwort, cat, dog, and Alternaria, participants underwent the ALEX2 test which allowed for detection of sensitization to cockroach-specific and cross-reacting molecules. Forty-eight participants took part in the study, of whom forty-six underwent the ALEX2 test. Among PAR patients with positive SPT results to cockroach extract only 2 had elevated IgE levels to cockroach specific allergens (Bla g 1 and Bla g 4). However, in substantial number of patients sensitization to cross-reacting allergens was demonstrated. This was associated with frequent sensitization to other arthropod extracts. A correlation was observed between cockroach allergy and allergy to edible insects such as crickets, locusts, and mealworms; seafood; house dust mites and storage mites; and wasp species, depending on the cockroach species. In our population of PAR patients sensitization to cockroaches is associated with a broader spectrum of cross-reactive allergens. These findings deepen our understanding of potential cross-allergenicity and may form the basis for personalized risk assessment and allergy treatment in patients with AR.