Quantitative inhalation bronchial challenge in ragweed hay fevery patients: a comparison with ragweed-allergic asthmatics.

Fourteen ragweed hay fever nonasthmatic patients comparably sensitive to a group of ragweed-allergic asthmatics by skin test and leukocyte histamine release were tested by quantitative inhalation bronchial challenge with ragweed extract. The provocation dose of ragweed extract producing 35% decrease in airway conductance was determined and designated PD35. PD35 values in the hay fever patients were not significantly different from PD35 values in the asthmatic group. These data suggest that carefully performed skin tests may be as diagnostically useful as bronchial challenge in routinely confirming the allergic etiology of seasonal asthma.