8. Madison, WI
Allergies have a genetic component. If only one parent has allergies of any type, chances are 1 in 3 that each child will have an allergy. If both parents have allergies, it is much more likely (7 in 10) that their children will have allergies. More Americans than ever before say they are suffering from allergies. It is among the country’s most common, yet often overlooked, diseases.