We believe that in allergic patients, due to their proinflammatory state and/or the lack of counter-regulatory mechanisms, the initial sIgE sensitization to Can f 1 and Fel d 1 (the most frequently found and in higher concentration levels) favors IgE sensitization to other molecular components; this hypothesis is supported by the observation that sensitization to Can f 3 and Can f 5 was exclusive in the rhinitis group, and they had a higher frequency of sensitization to Fel d 2 and Fel d 4. Here, IGHE is linked to rhinitis.