Many people feel like their allergies are extra intense this year, and there's a scientific reason why.Many people feel like their allergies are extra intense this year, and there's a scientific reason why. The Northeast's prolonged winter has led to extra sneezes and sniffles for the 50 million U.S. adults who have seasonal allergies. Because this season may be one of the worst in years, you may want to explore alternatives to over-the-counter allergy meds. Allergy specialist Dr. Lyndon Mansfield explains how antihistamines work and why they can make you sleepy. Plus, he answers if they're really the best allergy blockers, and how to find a treatment that's right for you. Bonus! 9 Best and Worst Foods for Heart Health