Eastern pine sensitivity in New England

The purpose of this study is to assess the frequency of clinical sensitivity to Eastern White Pine Pollen, 100 consecutive patients with the seasonal (SAR) or perennial (PAR) allergic rhinitis seen in the allergy clinic were prick tested with pine pollen extract, 8-tree mixture, histamine and negative control. Positive skin test (ST) was defined as a wheal greater than 3 mm larger than control, plus flare. Patients with a positive ST were then asked to stop antihistamine and other related drug, for 48 hours and challenged in a double blind manner with increasing concentrations of intranasal pine extract, starting at 1/100,000 w/v, followed by 1/10,000, 1/1000 and 1/100 at 20 minute intervals. The dose given was 0.15 cc by metered dose spray; one nostril received pine extract diluted in saline, the other received plain saline,. Rhinometric measurements were obtained before and 20 minutes after each challenge. Positive challenges were defined as 1) subjective feeling of increased stuffiness or rhinorrhea and 2) greater than 25% decrease in nasal airflow. Six patients (6%) had a positive ST to pine pollen extract and two of four patients with positive pine skin test had a positive FAST. Four of these were challenged intranasally, 2 had a positive challenge. All six patients had a history of spring SAR and positive reaction to 8-tree mix. Out of the 100 patients skin tested, 61 had spring SAR; therefore, the incidence of positive ST to pine in patients with spring SAR was 6/61 (10%). We conclude that pine pollen can be a cause of spring SAR in the New England area.