Hives (Urticaria) factsheet

Introduction

Hives, also known as urticaria, are a type of skin rash that can be raised, red and itchy.

Hives happen when chemicals like histamines are released from your child's skin cells. Histamines are chemicals made by the body to fight off illness and infection. This is called an immune response.

Immune responses, like hives, can be caused by:

illness and infection
allergic reactions – where the body reacts to a substance that is usually harmless
autoimmune conditions – where the body attacks its healthy cells
skin irritation – where the skin reacts to things like allergies, harsh chemicals, medication, stress, and heat.

Hives are very common in children. They can come and go over several hours and move around the body.

Signs and symptoms

Hives look like a red, raised rash on the skin. The raised lumps in the rash are called wheals.

Wheals can range in size from a few millimetres to several centimetres wide. They can feel itchy and hot and will show up in clusters.

Hives can appear and spread quickly before fading and moving to another part of the body. Each cluster can last for a few minutes to a few hours.

Your child may also have other symptoms at the same time as hives, including:

a runny nose
watery eyes
angioedema – swelling in the hands, feet, lips and eyes.

Diagnosis

Your child's doctor will be able to diagnose hives based on the look of the skin.

Acute hives

Acute hives are often caused by illness, infection, and allergy. They can last for several days.

Hives caused by an allergy usually start showing up 1 to 2 hours after your child has been exposed to their allergen.

Hives caused by an infection, like a virus, can show up 1 to 2 weeks after your child has been sick.

Sometimes, there is no obvious cause for the hives.

Allergy tests are not usually needed for acute hives.

Chronic hives

Chronic hives are hives that last longer than 6-8 weeks.

Allergies do not cause chronic hives. Usually, no cause is found except in rare cases where an autoimmune condition triggers hives.

Your child's doctor may order a blood test to try and figure out what is causing the chronic hives.

Physical urticaria

Physical urticaria is hives that are caused by physical factors.

This can include:

pressure or touching on the skin
sweating
exposure to heat, cold and sunlight
stress
chemicals and other skin irritants.

Hives caused by physical factors can appear in about 5-10 minutes and last 30-60 minutes before fading.

Treatment

Treatment of hives will depend on the type and your child's medical history.

The most common treatment is oral antihistamines. Antihistamines are a type of medication that blocks the effects of histamines in your child's body, which reduces the symptoms of the immune response.

Antihistamines will reduce the number of wheals on your child's skin. They can also treat other symptoms like swelling, runny nose and watery eyes.

Antihistamines are safe to use, but you should check with your doctor about whether they are effective for your child.

Children who do not respond to antihistamines or have chronic hives will need to see a specialist doctor for treatment.

They can see:

an allergist – allergy specialist
a dermatologist – skin specialist
an immunologist –immune system specialist
a dietician – a health professional who manages health conditions, diets, and nutrition.

Management

Hives and antibiotics

Some children will have hives at the same time as taking antibiotics for an infection.

The infection, rather than the antibiotics, usually causes hives.

If you are concerned, your child's doctor can organise a test in the hospital to see whether your child has an antibiotic allergy.

Hives and other medications

Some medications can make hives worse.

These include:

aspirin
codeine
non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen.

Paracetamol is generally safe, but check with your child's doctor if you are unsure.

Hives (Urticaria)