What to Know If Youre Breaking Out in Hives for No Apparent Reason

One reason hives can be so surprising is that they can be caused by many things you might not expect including stress and exercise. Most of these unexpected causes for hives aren’t serious, but some are a sign it’s a good idea to make a medical appointment.

Read on for more information about reasons you may have hives.

What are hives?

Hives are an itchy reaction on your skin. They happen when a chemical called histamine is released in your body.

They can appear anywhere on your body and can be tiny pinprick-sized bumps or large raised areas that cover an entire limb. Hives often appear red or pink on white or light skin. People with darker skin might have hives that are slightly lighter or slightly darker than the skin surrounding them.

No matter the color of your hives rash, all hives share these qualities:

  • raised
  • itchy
  • tender
  • round, oval, or uneven shaped
  • clearly defined border

Hives are also called urticaria. Sometimes, the cause of hives is obvious. For instance, you might have an immediate reaction to something you’re allergic to such as pollen or pet dander. However, the cause isn’t always clear. Hives can be sudden and surprising and seem to not have a cause.

What might be causing your unexpected hives?

Hives are a very common skin reaction that can come from some unexpected sources. Some causes you might not have thought of include:

What are the more common reasons for hives?

Hives are often caused by identifiable allergies. Avoiding these allergens can help you avoid breaking out in hives. Common hive triggers include:

  • shellfish
  • eggs
  • peanuts
  • milk
  • berries
  • citrus
  • animal dander
  • poison ivy and other plants
  • latex
  • wool, polyester, and other fabrics
  • pollen
  • grass
  • insect stings or bites
  • dust mites
  • mold
  • detergents and dyes

When it’s an emergency

Hives can be a sign of a serious allergic reaction that needs emergency medical emergency attention. It’s important to take action if you hives along with any of these symptoms:

  • wheezing
  • tightness in your chest or throat
  • trouble breathing
  • trouble talking
  • swelling in your throat, face, or tongue
  • nausea
  • lightheadedness

If you are experiencing any of these symptoms, call 911.

A doctor may prescribe you an epinephrine injector, such as an EpiPen, for future allergic reactions. They’ll teach you how to use it and answer any questions you might have. You’ll keep your epinephrine injector on hand and use it if you develop hives in the future.

You’ll still need to visit the emergency room after you use your epinephrine injector, but it can stop anaphylaxis from becoming deadly.

How are hives diagnosed?

A doctor can diagnose hives and help you find the cause. They might recommend you keep a food diary to find out if there is any link between food and your hives.

You might be sent to an allergist, a doctor who specializes in treating allergies, for additional testing. This might include blood work and urine tests to look for chemicals in your body that might tell the allergists what’s causing your hives.

You might also have a skin biopsy, especially if your allergist suspects vasculitis causing your hives. Hives that have lasted for longer than 6 weeks will likely necessitate testing for underlying chronic conditions.

Sometimes, a specific cause isn’t found. In this case, your hives will be diagnosed as idiopathic urticaria. The word “idiopathic” means unknown. In this case, your doctor will still be able to help you with a treatment plan, but you won’t be able to tell what to avoid to prevent hives in the future.

What is the treatment for hives?

Treatment for hives will depend on the severity of your hives and on the cause. For instance, you’ll need to avoid the cause of your hives if it has been found.

Your doctor will work with you to find the right treatment for you. Common options include:

  • Antihistamines. Both over-the-counter and prescription antihistamines block histamine and can treat hives. You might find that certain antihistamines are more effective for you than others. Sometimes a combination of antihistamines is recommended.
  • Anti-itch lotions. Lotions to calm down itching and redness can provide relief from hives and prevent scratching.
  • Antibiotics. Hives that are linked to bacterial infections can be treated with antibiotics
  • Corticosteroids. Corticosteroids can be taken on a short-term basis to help with severe cases of hives.

The bottom line

Hives can sometimes be surprising and have no obvious cause. There are actually a wide variety of things that can cause hives, including stress, colds, exercise, and temperature changes. Chronic hives can point to an underlying condition such as lupus.

An allergist can help you determine the cause of your hives and start treatment.

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