Hives (Urticaria)

Also Known As: Urticaria

Overview

What Is Hives?

Hives (or urticaria) are red raised bumps or welts on the skin. They are a common skin reaction to something like an allergen (a substance that causes allergic reactions). Hives can appear anywhere on the body and can look like spots, blotches, or bumps. Sometimes they can look connected to each other.

How Long Does Hives Last?

Hives often lasts anywhere from a few hours to a couple of weeks, and new ones might replace those that fade. When hives appear for six weeks or less, it's called acute hives. When they stay longer than six weeks, it's called chronic hives.

Top Things to Know

• Hives are raised bumps or welts that can appear anywhere on the body.
• They have many causes but are often caused by allergic reactions to foods, medicines, or stings. 
• Treat symptoms with over-the-counter antihistamines or creams, cool compresses, or oatmeal baths.
• Get help right away if your child has symptoms of a severe allergic reaction (anaphylaxis), like trouble breathing or swallowing or swelling of the face, lips, tongue, or throat. Give epinephrine if you have it. 

Signs & Symptoms

What Does Hives Look Like?

The hallmark red raised welts are the main sign of hives. The welts can:

• have a pale center
• appear in clusters (several hives close together)
• change shape and location in a matter of hours
• be small or large
• itch, sting, or cause a burning sensation

Hives & Angioedema

Some people who get hives also have angioedema, a condition that can cause puffiness and swelling of the eyes, lips, tongue, hands, feet, genitals, or throat. Other symptoms can include nausea, vomiting, diarrhea, or belly pain.

When Is Hives an Emergency?

Sometimes hives can be a sign of a serious allergic reaction, called anaphylaxis. Anaphylaxis can lead to breathing trouble, a drop in blood pressure, a loss of consciousness (passing out), and if not treated with epinephrine, death.

Causes

What Causes Hives in Kids?

The red welts of hives happen when mast cells — cells that help protect the body from threats (but can sometimes overreact) — release the chemical histamine in the bloodstream. This makes tiny blood vessels under the skin leak. The fluid pools within the skin to form spots and large welts. This can happen for a number of reasons, but sometimes the cause is not found. Known causes of hives inlude:

Allergic Reactions

Sometimes hives is part of an allergic reaction. Allergic reactions might happen after exposure to:

• foods, like shellfish, peanuts, tree nuts, milk, eggs, fish, wheat, soy, sesame, or other foods
• medicines, like antibiotics and allergy shots
• pets and other animals
• pollen
• insect bites and stings

Viruses

Hives is often caused by a viral infection. This is called viral hives. Viral infections that can cause hives include common viruses that kids get, such as upper respiratory tract infections.

Other Causes

Other causes of hives include:

• bacterial infections
• exercise
• anxiety or stress
• sun exposure
• exposure to cold, such as cold water or snow
• contact with chemicals
• scratching (dermatographia)
• pressure on the skin, such as from sitting too long or carrying a heavy backpack over a shoulder

Hives due to physical causes (like pressure, cold, or sun exposure) is called physical hives.

Chronic Hives

It can be hard to figure out what causes chronic hives. Sometimes it’s caused by other medical conditions, like celiac disease or lupus. Often though, doctors don't know what causes chronic hives.

When Should I Call 911?

Get help right away if your child has signs of a severe allergic reaction (anaphylaxis). This includes breathing trouble, belly cramps, a drop in blood pressure, dizziness, or a loss of consciousness (passing out), or angioedema. Give epinephrine immediately if you have it, or call 911 if you do not.

Diagnosis

How Is Hives Diagnosed?

Most of the time, a doctor can diagnose hives just by looking at the skin. To find the cause, you may be asked questions about your child's medical history, recent illnesses, medicines, and exposure to things that may have caused an allergic reaction.

The doctor may ask you to keep a daily record of activities, such as what your child eats and drinks, and where the hives tend to show up on the body. The doctor might recommend tests — such as blood tests, allergy skin tests, and tests to look for other conditions that can cause hives.

To check for physical hives, a doctor may put ice on your child's skin to see how it reacts to cold or place a sandbag or other heavy object on the thighs to see if the pressure will cause hives.

Treatment & Home Care

How Is Hives Treated?

Acute Hives

Mild acute hives usually doesn’t need treatment and will go away on its own. If a definite trigger is found, avoiding it is part of the treatment. The doctor may recommend antihistamine medicine to block the release of histamine in the bloodstream and prevent allergy symptoms, like itchiness, and more breakouts.

Full body hives, especially if combined with other symptoms, may be a sign of a more severe reaction that requires epinephrine.

Chronic Hives

For chronic hives, the doctor may suggest a non-sedating (non-drowsy) prescription or over-the-counter antihistamine to be taken every day. Not everyone responds to the same medicines though, so it's important to work with the doctor to find the right one for your child.

If a non-drowsy antihistamine doesn't work, the doctor may suggest a stronger antihistamine, another medicine, or a combination of medicines. In rare cases, a doctor may prescribe a steroid pill or liquid to treat chronic hives. Usually this is done for just a short period (five days to two weeks) to prevent harmful steroid side effects.

Epinephrine

Kids who may have a severe reaction should always have two doses of epinephrine with them. Epinephrine can be given with an auto-injector or, for some kids, as a nasal spray.

Epinephrine enters the bloodstream and works quickly against serious allergy symptoms. Kids and teens who have severe allergies should always have two doses of epinephrine with them, including at school, sports, jobs, and other activities. The devices are small and easy to use.

If the doctor prescribes epinephrine for your child, they will show you how to use it. Two devices should always be with your child in case one does not work, or your child needs a second dose.

How Can I Help My Child Feel Better?

Encourage kids to not scratch the hives because this can irritate the skin and even lead to an infection.

Your child also may get some relief from a cool or warm (not hot) bath. Oatmeal baths can help some kids feel less itchy. Kids should wear loose, breathable clothing to help them feel more comfortable.

Whenever possible, avoid things that cause hives. Kids who have had hives in the past and know the cause can help prevent them by avoiding these triggers.