For most healthy people, an outbreak of hives is as worrisome â€” and temporary â€” as catching a cold. But for those who have chronic hives, or urticaria, the condition can seem relentless.
â€œChronic idiopathic hives are itchy red welts that persist for at least six weeks and have no known cause,â€ says Miriam Anand, MD, an allergist with Allergy Associates and Asthma in Tempe, Arizona. The condition is marked by periods of exacerbation and remission, and for many who have it, the hives may persist for more than five years.
If you have chronic hives, itâ€™s important to try to identify your triggers, if possible, and take steps to avoid them so you can lower the risk of an exacerbation. While you may already be aware of common triggers, such as allergies to pollen, pet dander, and shellfish, here are some lesser-known triggers of chronic hives:
1. Tooth decay and other infections
2. Working out
Could you be allergic to your own sweat? Yes, says Dr. Anand. Although the cause of hives triggered by exercise is sometimes thought to be an increase of body heat, what actually triggers hives when you work out is sweat. Does that mean you should skip exercise if you have chronic hives? Not necessarily. Talk to your doctor if you suspect this may be one of your triggers â€” he or she may recommend taking a dose of antihistamine just before you exercise to help prevent a flare-up.
4. Artificial colors and preservatives
If sunlight triggers your hives, youâ€™ll probably know within just a few minutes of exposure to one of these three types of light: long-wavelength ultraviolet (UVA), short-wavelength ultraviolet (UVB), and sunlight that doesnâ€™t contain ultraviolet rays, such as sunlight through a window covered with a protective film that blocks UVA and UVB light. Hives triggered by sunlight usually disappear within a day, but in the majority of cases, they recur. Fortunately, sunlight is a rare trigger, and itâ€™s easier to test for than other potential triggers.
6. Cold temperatures
Winter is not exactly the most popular season, and with good reason for those who live with chronic hives: The cold can trigger a flare-up in some. Besides the weather, other cold-related triggers include chilly foods and swimming pools. For people who are allergic to the cold, full-body immersion in a swimming pool, in particular, can trigger a severe reaction that involves not just hives but allergic shock (anaphylaxis) and loss of consciousness.
Fortunately, itâ€™s easy to find out whether cold is one of your triggers: Your doctor can administer a simple test that involves placing an ice cube on your skin for five minutes to see if a reaction occurs. If it turns out that cold is a trigger for you, your doctor will recommend that you protect your skin from the cold and take your medications as prescribed.
7. An autoimmune disease
However, says Anand, â€œwe donâ€™t know if the disease causes urticaria or if the personâ€™s propensity to have an autoimmune reaction causes it. But if we donâ€™t find any triggers when we test for allergens, then we look for an underlying infection or autoimmune disease.â€ Anand adds that treatment for that condition can help clear the hives.
Discovering Your Triggers
Other potential triggers of chronic hives include heat and aggravating your skin by scratching it or putting pressure on it (for example, by wearing tight clothes or sitting on a hard surface). Keeping a diary in which you record when and where your symptoms developed or worsened can help you and your doctor find clues and pinpoint your triggers, says Anand. But if even that doesnâ€™t help, don't lose heart: For most people, even chronic hives whose cause is unknown gradually disappear on their own over time.
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