Skin tests and bronchial, nasal and conjunctival provocation tests with pollen and animal dander allergens were performed in thirty patients with atopic asthma. In vivo test results were compared only when the same batch of allergen had been used. A nasal reaction was mostly elicited at a lower concentration of allergen than was needed to elicit a bronchial reaction (P < 0·01). Positive nasal reactions were often obtained when the corresponding bronchial tests were negative. The conjunctiva reacted to lower concentrations than the bronchi in a third of the instances of testing, with most of these being tests with mugwort allergen (P < 0·05). A positive skin test in cases with a negative bronchial challenge test was often accompanied by a positive nasal test and in some cases by a positive conjunctival test.
It is concluded that nasal or conjunctival provocation tests do not replace bronchial challenge tests. In an asthmatic patient who gives no reaction to bronchial challenge with a particular allergen, a positive skin test may reflect a nasal allergy.