Many people develop hives, also known as urticaria, as a result of exposure to allergens. While hives usually disappear within 24 hours, some people live with hives that last more than six weeks and cause more unpleasant symptoms. But diagnosing chronic, or long-term, hives can be difficult, leading to frustration for both you and your doctor. Almost 1.5 million people in the United States experience chronic hives, or chronic idiopathic urticaria (CIU). And while this condition generally isn’t life-threatening, it can affect your enjoyment of your daily life. Working with your dermatologist or allergist is the best way to arrive at an accurate CIU diagnosis. Once the problem is positively identified, your doctor can implement a treatment plan that may be most effective for you. What are chronic hives? Like acute hives, CIU results in welts that may appear anywhere on your body. These welts typically vary in size and shape and may be discolored compared to your surrounding skin. They may also occur along with other symptoms, like swelling around the hives or severe itching. But unlike acute hives, chronic hives don’t go away quickly. Instead, CIU may last for several months or longer. Typically, doctors consider a diagnosis of chronic hives if the hives have been present for six weeks or longer without disappearing completely. Recurring hives, or hives that come and go over periods of time, also point to CIU as a possible diagnosis. What causes chronic hives? Unfortunately, the cause of most chronic hives is idiopathic; that means doctors don’t know why chronic hives occur. It’s thought CIU may be caused by exposures to certain triggers. These triggers may promote an allergic reaction within your body, resulting in the release of histamine and other chemicals into your bloodstream. These types of substances cause increased levels of inflammation within the body, which may result in hives on your skin. Possible triggers which may cause chronic hives include: Exposure to cold, heat, or sunlight Infections Insect or parasite bites Some medications Stress, including stress placed on the body during exercise Other research indicates CIU may result from the overactivity of your body’s own immune system. In some individuals, the immune system attacks normal body tissues and hives occur as a result of this attack. Scientists have also witnessed associations between chronic hives and other chronic conditions, like thyroid disease and celiac disease. Researchers are working hard today to discover the underlying causes of CIU, and already their work has resulted in more treatment options than ever before. How will my doctor diagnose my hives? Many doctors begin the diagnostic process with a thorough discussion of your symptoms, including how severe they are and how long they last. Your doctor will also ask you about your past medical history, any other medical conditions you may have, and what medications you take. Then, your doctor may examine your skin to determine the severity of your condition and how it might best be treated. Because we don’t know the exact cause of chronic hives, and because many other conditions can cause similar welts to develop, your dermatologist or allergist may recommend several diagnostic tests to rule out other diseases and identify any underlying medical problems. Because it’s important to make sure nothing more serious is causing the hives, it may take time to accurately diagnose your condition. The diagnostic tests may include blood work to monitor inflammation levels and help identify allergens that may cause your symptoms. In rare cases, a skin biopsy is necessary to rule out other issues. During a skin biopsy, your doctor painlessly removes a small sample of a hives welt for further evaluation in a laboratory. Although it can take time to reach a chronic hives diagnosis, it’s crucial to take each step in order to get an accurate assessment of your condition. Once you reach that point, you and your doctor will work together to find the most effective treatments for you. Your personal treatment plan depends on many factors, including your overall health, your medical history, and any known hives triggers. It’s important to follow your doctor’s treatment recommendations closely and report whether or not a prescribed treatment works. You may need to try several treatments before finding what works. Because chronic hives often have no identifiable cause, diagnosing this condition can be difficult. If you think you may have CIU, it’s important to work together with your doctor to identify any possible causes. Even though a positive diagnosis can take a while, it’s still possible to figure out what’s going on with your body. That way, you can find the best treatment options for you.