The Role of Target Organ Diagnostic Approach in Seasonal Allergic Rhinitis: Nasal Smear Eosinophils

BACKGROUND Allergic rhinitis (AR) related to local weeds pollen sensitization (Chenopodiaceous family) is the most common cause of respiratory allergy in Kuwait. Local nasal accumulation of different cells typical of allergic inflammation is responsible for clinical symptoms of AR. Although nasal smear for Eosinophils (NSE) is one of the earliest included valuable test in diagnosis of AR, with time is underestimated. AIM Explore possible correlation of natural pollen allergen stimulation with appearance and quantity of Eosinophils in nasal smear. METHODS A group of randomly selected patients with clinical history suggestive for seasonal AR (SAR), who came to Al Rashed Allergy Center in period from October 2014 to October 2015, obtain Nasal Smear for Eosinophils as a screening test before further diagnostic evaluation. Nasal samples were collected by passing a sterile swab, from each nasal cavity, along the medial surface of the inferior turbinate 2 to 3 times and the specimen smeared on a clear glass slide. Nasal smears were examined by light microscopy after staining with hematoxylin and eosin stain. Skin prick test is performed in all symptomatic patients with a battery of inhalant allergens that include local pollens. The control group was recruited, with their voluntary consent, from the medical stuff with a negative history of any allergic nasal symptoms. In this group we performed only nasal smear for Eosinophils. Air Biology Laboratory Kuwait provided us with daily pollen count. RESULTS From total 158 study participants, 132 had SAR symptoms and are divided in four groups. Fifth, control, group is non symptomatic. For 38.6% of symptomatic patients NSE were positive, while 45% of these patients have negative SPT. From 62.1% NSE negative patients, 37.8% have negative SPT. Our results showed expected positive correlation of NSE positive patients with pollen season in Kuwait, in SPT positive group. However, presence of Eosinophils in nasal smear was moderate to high also in patients with negative SPT during the highest peak of season, in contrast to control group. CONCLUSION NES showed moderate sensitivity, relatively high specificity and importance as screening test in SPT negative patients. Evaluation of AR demand wide and improved diagnostic approach due to significant number of SPT negative patients with positive NSE based on natural allergen stimulation. Our results emphasize locale allergic response of nasal mucosa and importance of target organ diagnostic approach.