January 19, 2023
Hives (also called urticaria) are a familiar ailment to many. About one in four people have had hives during their lives. Fortunately, hives are usually easy to treat. Most cases are mild and last only a few hours, although chronic hives can last for months or years.
Hives are a type of rash (raised, itchy welts) caused by the body’s immune response to allergens or sometimes infections. Hives can be found on any part of the skin including the face and scalp.
There are many reasons hives form. Most commonly, hives are caused by an allergic response. When your body is exposed to an allergen such as a food, medication, or pollen, the body reacts by stimulating allergy cells (mast cells) on the skin’s surface, causing the release of certain substances (like histamine). These chemicals help protect the body from infection, but they can also cause itching, swelling, and hives.
While some hives are caused by allergies, there are many other causes. Triggers like temperature changes, stress, illnesses, and infections can also cause hives. In many cases, the cause cannot be identified.
Hives are usually very itchy and can affect the skin on any part of the body. Hives often disappear and reappear throughout the length of the outbreak. Each individual welt may last from 30 minutes to 24 hours. Fading welts may be replaced by new ones until the outbreak resolves. Hives usually appear suddenly. Normally after a few hours, the hives on the skin will quickly disappear on their own. However, chronic hives can last for many weeks or months.
Hives appear in groups of bumps and raised welts on the skin. They can look different on various skin tones, appearing red with pink-to-white centers on fair skin, and dark with lighter centers on darker skin. Hives usually have well-defined edges or borders. They can vary widely in shape and size. Hives may be small and round, or large and irregular. They may also spread to new areas of the skin, become larger, change shape, or join together to make larger areas of swelling. One way to check if you have hives or another type of rash is to press on one of the welts. If the bump is raised above the rest of your skin and turns white when you press on it (this is called “blanching”), it is probably a hive.
Hives can be classified as acute or chronic. Acute hives are most often short-lived, coming and going for less than a few weeks. Any hives that clear up within 6 weeks are considered acute. If the hives last longer than that, they are called chronic hives. Hives can also be categorized by what causes them. Symptoms may vary depending on the type of hives that you have.
1) Hives caused by allergic reactions
If you have known allergies, such as to foods, pet dander, insect stings, or medications), hives may be a sign of an allergic reaction. Sometimes, allergic reactions can cause a life-threatening emergency called anaphylaxis. Hives may appear along with symptoms like severe swelling, dizziness, nausea, vomiting, and difficulty breathing. If someone is experiencing anaphylaxis, call an ambulance. Hives that last for many days, weeks, or months (chronic hives) are much less likely to be related to an allergic trigger. In general, if you have been unable to easily identify a trigger for your hives, they are unlikely to be related to foods or other allergens, however consulting with an allergist may be helpful.
2) Viral-induced hives
One of the most common causes of hives all over the body is viral infections. Hives can form when the immune system has an exaggerated response to a virus, releasing too much histamine. Viral infections are the main cause of hives in children. Influenza, mononucleosis (“mono”), RSV (respiratory syncytial virus), the common cold, urinary tract infections, and many other viruses can cause hives in children and adults. We now know that COVID-19 is also a virus that causes hives in some patients. Viral infection hives may occur all over the body. These hives can appear while you are sick or shortly after you’ve recovered from your infection. Hives after a viral infection usually stay on the skin for days or weeks. Sometimes, hives can be the only sign your body is fighting an infection. You may not have a fever, cough or other signs of illness. This is especially common when it is a virus/infection your body has encountered in the past and you have some immunity to it (either from previous infection or vaccination).
This type of hives happens when your skin reacts to being scratched. Your scratches can become red, itchy, and inflamed. The hives may look like raised lines or ‘writing on the skin’. Dermatographia normally disappears quickly without needing treatment. It can be present in patients with other types of hives as well.
4) Temperature-induced hives
For some people, hives can appear in response to changes in temperature. Exposure to extreme cold or heat, including body heat from exercise, can cause temperature-induced hives. It is common for many types of hives and itching to worsen after getting out of a hot shower for example, when the body goes from hot to cool very quickly.
5) Chronic hives
Hives that last for six weeks or more are called chronic hives (also called chronic urticaria). These uncomfortable, itchy hives can reoccur for months or even years. Unfortunately, it can be difficult to identify and treat the cause of chronic hives. Many patients with chronic hives have a family history of autoimmune disease (celiac disease, lupus, type 1 diabetes, rheumatoid arthritis, Crohn’s disease etc.) and chronic hives are more common in patients with certain conditions, such as autoimmune thyroid disease. We are still learning a lot about what causes chronic hives and who may be at risk for developing them. Fortunately, even chronic hives are usually very treatable. Consulting with an allergist can give patients more options for management.
Hives and other rashes can be a symptom of COVID-19. In fact, a study in 2021 found that 8.8% of people who tested positive for COVID-19 also noticed skin changes, such as hives and rashes. When hives are caused by COVID-19, they often appear in the early stages of the illness. Many times, they are the first symptom to appear. The hives may last throughout the COVID-19 infection and continue for many days after the patient is no longer contagious. Usually, antihistamines will help clear up the rash. As for other viruses, rash or hives may be one of the only symptoms of COVID-19 infection.
Most hives go away on their own within a few hours. However, if your hives are very uncomfortable or last for multiple days, there are many options available. The most common treatment for hives is oral allergy medications called antihistamines. These medications can reduce itching, swelling, and other symptoms of hives and allergies. Many antihistamines are available over the counter. Some can cause drowsiness, which might be beneficial if your itching is keeping you up at night! Newer antihistamines are less likely to make you drowsy and therefore work better for daytime use. For more severe cases, seeing your doctor or an allergist can be helpful, as prescription medications may be necessary. If your hives were caused by allergies, a skin test may be used to find out what you’re allergic to. You can then avoid the allergen and use allergy medications if you are accidentally exposed to it.
There are some times when emergency care for hives is needed. Hives on faces should be monitored closely in case they spread to sensitive areas such as the eyes or mouth. Hives on your throat, mouth or tongue can cause swelling that blocks your airway, making it difficult to breathe. If you have hives on these areas, immediate medical attention is necessary.
Hives can sometimes signal the start of a life-threatening reaction (anaphylaxis). If you have symptoms with the hives such as severe swelling, vomiting, coughing, wheezing, dizziness, or difficulty breathing, you should call 911 or visit the emergency room immediately. The best treatment for anaphylaxis is an injection of epinephrine. Epinephrine is a type of adrenaline that relaxes the muscles in the airways and treats severe allergic reactions. The hospital will monitor you for a return of symptoms and provide a second epinephrine shot or other medications as needed. If you have a known allergy, such as to foods or stinging insects you may have been prescribed an epinephrine auto-injector for use at home as well. If you ever have to use your epinephrine auto-injector, you should still seek emergency care in order to be monitored for the return of allergic symptoms.
Hives are usually a mild condition that can be treated at home. However, if your hives last for more than three days, you should see a healthcare provider. Your provider can examine the hives, rule out other conditions, and prescribe medications to ease your symptoms.If you suspect that your hives were caused by an allergic reaction or there has been no identified trigger for your hives, you may wish to see an allergist. An allergist may recommend allergy testing if appropriate and can certainly help with treatment options. WellNow has several specialized allergy centers so you can get trusted, expert advice and treatment.
If scheduling or location makes it hard to see your regular doctor, an urgent care provider is a great option for hives treatment. WellNow Urgent Care is one of the fastest-growing urgent care providers. We have many U.S. locations to serve you. Try our easy-to-use location finder to select your clinic. Then, take advantage of our extended hours and visit us at the best time for you. Let us help you along your path to recovery.