MNN - Mother Nature Network

It starts with a tickle in your throat. As you reach for a tissue, you notice birds singing from their nests as freshly bloomed flowers bob in the sunlight. Spring has sprung, and it has kicked your allergies into high gear. As determined by the Asthma and Allergy Foundation of America (AAFA), here are the 12 worst U.S. cities out of 100 cities ranked for allergy sufferers for the 2011 spring season.