Allergic disorders are among the most prevalent health problems around the world, particularly in low and middle-income countries.1 Allergies impose a high economic burden and have a significant negative impact on patients’ quality of life, especially in students when allergies interfere with academic life.2 Allergens are the most common trigger of allergic symptoms and the pattern of sensitisation varies in different societies because of lifestyle and genetic background. Identification of the prevalent allergens in each area and the general population has an important role in the prevention and management of allergic disorders. Since Iran has a high population diversity, as well as different geo-climatic conditions, we aimed to evaluate the skin sensitivity of medical students in Birjand, Iran by using 80 different allergens.
SUBJECTS AND METHODS
Medical students were randomly selected and provided informed consent to participate in the study. Demographic data and the presence of different allergic disorders amongst the students were evaluated using a questionnaire. Skin prick tests were performed with 80 different extracts, including foods, pollens, and indoor allergens.
There were 144 medical students (mean age: 21.1 years; range: 19-30 years; male/female ratio: 0.63) enrolled in this study. The prevalence of asthma, allergic rhinitis, and eczema was 2.77%, 40.00%, and 12.50%, respectively. At least one positive reaction was seen in 58% of the participants, and more than half were polysensitised. The most common allergens were Salsola kali (48.61%), a mixture of common weed pollens (45.38%), Chenopodium Album (40.97%), and a mixture of tree pollens (29.86%). They also were the most potent allergens and had the largest mean wheal size (29.5, 15.3, 11.8, and 9.9 mm2, respectively). Tomato, orange, walnut, mustard, and pomegranate were the most prevalent food allergens (4.86%, 3.47%, 3.47%, 3.47%, and 3.47%, respectively). There was no significant difference in sensitisation between males and females.
The results of this study showed high, medium, and low prevalence of allergic rhinitis, eczema, and asthma, respectively, which is similar to the results of other reports from this area that studied the general population.3,4 In the case of prevalent aeroallergens, weed pollens, particularly Russian thistle and Lambs quarter, were the most common and potent allergen, in concordance with the results of another study in the region.5 Skin sensitivity to indoor allergens, particularly mites and moulds, was quite low, which can be explained by the geo-climatic situation of Birjand. Two other studies have also confirmed the lack of mite growth in Birjand6 and in many other parts of Iran.7 In the case of food allergens, the pattern of sensitisation differed from the results of most other studies in Iran, which report both cow’s milk and egg as the frequent food allergens in children.8
The results of this study confirmed high rates of allergic rhinitis and skin sensitisation to plant pollens, particularly weeds and grasses, while the sensitivity to indoor allergens and food allergens was low.