Comparison of nasal responsiveness to histamine, methacholine and phentolamine in allergic rhinitis patients and controls.

In a selected group of rhinitis patients with an IgE-mediated allergy to house dust mites the nasal response to insufflation of histamine chloride, methacholine and phentolamine was demonstrated to be higher than in a control group. With the methods used histamine chloride was better at discriminating between healthy subjects and patients than methacholine or phentolamine. This discrimination was shown by assessing the severity of reflex-mediated symptoms such as the number of sneezes and the amount of secretion, and not by differences in nasal airway resistance.