This story isn't about the kind of hives that pop up and then promptly disappear. Instead, chronic hives, or chronic idiopathic urticaria (CIU), are uncomfortable, itchy red welts and can last six weeks or longer. They affect approximately 1.5 million people, and they're usually treated with antihistamines and immunosuppressive drugs. But it isn’t uncommon for people living with CIU to use complementary therapies to help manage symptoms and prevent flare-ups. Following a low-histamine diet is one them. Here's what you need to know if you'd like to give it try, too.