Estimates from a skin test survey suggest that allergies affect as many as forty to fifty million people in the United States, according to the American Academy of Allergy, Asthma and Immunology. Experts say some of the most common irritants are grass, pollen and ragweed. We spoke with Cr. Eric Brestel, an immunologist with allergy east in Greenville, who says allergy sufferers should refrain from opening doors and windows during this time of year. Dr. Brestel says the recent rainfall will give sufferers some short-term relief, but he says the pollen will continue to be an issue when the warm weather returns.