NONSPECIFIC NASAL PROVOCATION IN CHILDREN WITH CHRONIC ALLERGIC RHINITIS

Twenty-three children with chronic allergic rhinitis (Group A) and ele ven normal non-atopic subjects (group C) were submitted to non-specifi c nasal provocation tests with histamine (0.03; 0.06; 0.125; 0.25; 0.5 ; 1.0; 2.0 and 4.0 mg/ml), and one week later with methacholine (0.025 ; 0.1; 0.25, 0.5; 1.0; 2.5; 5.0 and 10.0 mg/ml). Measurements of total nasal resistance were performed by active anterior rhinomanometry (Be rger, S.A.) and symptoms were recorded. Challenges were carried out in the morning with all children in an acclimatized room (25 degrees C/7 7 degrees F). Concentrations of the tested drugs were increasingly ins tilled and after 5 min were followed by total nasal resistance FEV(1), and FVC measurements considering as positive those tests in which tot al nasal resistance had a 100% increase, we observed that both histami ne and methacholine caused an increase in total nasal resistance as in stilled drug concentration rose; histamine provocations were significa ntly more positive among group A than group C patients (91% sensitivit y, 80.8% positive predictive value). This was not observed with methac holine (55% sensitivity, 75% positive predictive value). In neither pr ovocation was there correlation between the concentration that induced a positive response and symptoms. There were no changes in spirometri c values during the tests. Nasal provocations with histamine and metha choline are safe and well tolerated. Histamine seems to be more adequa te for differentiating children with allergic rhinitis from normal con trols.