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What are hives?
Hives are red or white raised bumps on your skin that usually itch. They are triggered by an allergic reaction. Hives can be acute, lasting a few days to up to 6 weeks, or chronic, appearing on and off for more than 6 weeks.
It’s very common for illnesses and infections to cause hives. About 80% of cases of acute hives in children are caused by viral infections like the common cold. It’s harder to pinpoint a cause for chronic hives, but they can be caused by a chronic condition like lupus or thyroid disease.
Hives look like raised flat bumps that appear on your skin anywhere on your body. The bumps look red or white, but the color may not be as obvious on darker skin tones. They often itch but can also burn or sting. The raised bumps can be separate or merge together into a larger patch.
The majority of hives only last a few days. If you have chronic hives, you might notice that they change size and shape or disappear and then reappear.
Hives can also be part of a larger allergic reaction, which can include dangerous symptoms like difficulty breathing or swallowing. Go to the ER or call 911 if you have these symptoms.
Why do illnesses cause hives?
When you’re sick, your immune system starts working to fight off the invader. For some people, the immune cells in your skin, called mast cells, are also activated. The mast cells release histamine, a chemical that brings on the itching and redness of hives. The hives usually appear when the immune system is clearing the infection out of your body, so it can happen a week or so after you first get sick.
Are children more likely to get hives?
Hives from illnesses are very common in children, since the infections that can cause them occur more often in younger kids. For example, children often get six to eight colds a year. It is because their immune systems are still being developed and they are constantly exposed to germs in schools and daycares.
Viruses and bacteria that cause hives
Hives may not be the first symptom you think of for these common viral and bacterial infections, but they can all potentially cause the red itchy spots.
- Common cold: This viral infection that targets your nose and upper respiratory tract can also trigger hives. Colds are usually mild and go away in 1–2 weeks.
- COVID-19: There is a lengthy list of symptoms for COVID-19, which is caused by a virus, and it includes hives, which can last 2–12 days.
- Urinary tract infection: Along with its trademark symptoms of burning while urinating and constantly feeling like you need to urinate, a UTI can also cause hives. UTIs are caused by bacteria and can be treated by antibiotics.
- Mononucleosis: Another viral infection, mono can cause hives in rare cases. It’s most common in teenagers and young adults and is very contagious.
Chronic illnesses that cause hives
There are many types of chronic illness, but autoimmune diseases are the most likely to cause hives. An autoimmune disease is when your immune system mistakenly attacks your own body. Here are some that can cause hives:
- Celiac disease: With celiac disease, your immune system reacts whenever you eat gluten (the protein found in wheat, rye, and barley). That immune reaction can trigger hives, which are called dermatitis herpetiformis when connected to celiac. It happens in up to 25% of people with celiac and is treated with an oral antibiotic (Dapsone).
- Diabetes: Type 1 diabetes is an autoimmune disorder, which is why it’s been linked to hives. And while type 2 diabetes is not an autoimmune disorder, some people may get hives from the insulin or medications they’re taking to help manage blood sugar levels.
- Lupus: Lupus is an autoimmune disease that causes chronic inflammation throughout the body. Around 10% of people who have lupus will also have hives. Your provider will want to look at your hives to make sure they aren’t a side effect of medication or a sign of a different disease.
- Rheumatoid arthritis: Caused by an overactive immune system, rheumatoid arthritis can trigger hives. Some medications for rheumatoid arthritis suppress the immune system and can also cause hives (but those hives tend to be just around the spot of the injection).
- Thyroid disease: The link between thyroid disease and skin issues is so strong that sometimes your dermatologist may be the first person to notice something is going on with your thyroid.
- Vitiligo: Vitiligo is a skin disorder that causes large discolored patches all over the body, but it can also cause hives.
Hives caused by a viral or bacterial illness will usually go away in a week or two. An antihistamine like Benadryl can be helpful, though it does cause drowsiness.
If your itching is severe, talk to your healthcare provider about other treatment options. If the itch doesn’t improve after taking antihistamines, your provider may prescribe an oral steroid.
For hives caused by a chronic illness, a dermatologist may be able to recommend more long-term ways of managing the condition. Your provider that treats your underlying disease can also help, since managing your primary condition can improve hives.
If your hives are caused by an allergic reaction and you notice signs that you are going into anaphylaxis, which is when your throat is closing up and you can’t breathe, you need to call 911 or go to the ER immediately since that is a life-threatening condition.
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