Sánchez J, et al. Allergy Asthma Immunol Res. 2021 Sep;13(5):746-761. https://doi.org/10.4168/aair.2021.13.5.746

Keywords: Allergy and immunology; Dermatitis, atopic; Eczema; Hypersensitivity; Tropical medicine

In different epidemiological medical tests —specifically the ones tested in tropical regions— a substantial increase has been observed in the prevalence of atopic dermatitis. ISAAC is the largest international test to analyze dermatitis epidemiology, which tested the prevalence of the most prevalence of the most common childhood atopic diseases in almost 200 points in more than 50 countries around the world. According to that test, the prevalence of dermatitis in tropical countries, especially in those from Latin America, was higher in comparison with other regions with a mode of 15%. That percentage among those populations using the same survey suggests that some genetic and environmental factors have an important effect on the development of dermatitis. However, considering that the surveys were completed by participants, it is possible that there was a misidentification of the disease and a tilt made from the patient, therefore comparative tests with cohort studies of the region are needed in order to determine if they are clinically relevant or not. In this article, we compare the prevalence of dermatitis reported by the ISSAC in tropical countries and some studies using other commonly diagnostic methods tested in the region.

Background. IgE sensitization (atopy) to pets is commonly evaluated using pet dander extracts. However, the diagnosis by components seems to be more adequate to evaluate the clinical relevance (allergy) of sIgE sensitization.Objective. To study the association between IgE sensitization to pet allergen components and clinical symptoms.Methodology. Dander extracts and sIgE levels to pet components (Can f 1, Can f 2, Can f 3, Can f 5, Fel d 1, Fel 2, and Fel 4) were measured in a rhinitis group (n=101) and a control group (n=68). Nasal provocation tests with pet extract were done in patients with atopy to pets.Results. Dog (34.6% vs. 23.5%) and cat dander (26.7% vs. 8.8%,p=0.05) IgE sensitization was frequent among rhinitis and no-rhinitis subjects, and it was similar to dog (29.7% vs. 20.5%) and cat (18.8% vs. 8.8%) components. Polysensitization for dog (3.1, 95% CI: 1.5 to 6.1,p<0.001) or cat (2.5, 95% CI: 0.8 to 8.0,p=0.01) components was the principal risk factor for a positive nasal provocation test. Additionally, positive nasal provocation test with one animal increased the risk of atopy and positive nasal provocation test to others animals. Pet ownership or asthma was not associated with increased risk of atopy or positive nasal provocation test.Conclusions. Sensitization to pet dander extract identifies atopic patients, but its utility to predict clinical relevance is poor. Allergenic components could help to define the clinical relevance of sensitization to furry animals and could reduce the need for provocation test.