Hives are slightly raised, red patches of skin called wheals (or welts). They occur in groups on any part of the body, and can look like mosquito bites. They are often itchy, but sometimes also sting. The medical word for hives is urticaria (er-tuh-care-ia).

Hives can be a sign of an allergic reaction to things like food or an insect sting. Hives are very common – one out of every five people will have hives at some time in their life. It is common for hives to occur in children where there is no identifiable cause, this is called idiopathic urticaria. 

Treatment includes medicines and avoiding known triggers. The triggers may be different for each child, and it is common that a trigger cannot be identified. 

Signs and symptoms of hives

If your child has hives, they may have raised round wheals that look like mosquito bites. The wheals are red on the outside and can be white in the middle.

• Hives are normally very itchy, but can also sting.
• A single wheal often lasts several hours before fading without trace.
• The wheals appear in batches or clusters. New batches may develop as old areas fade away. 
• Often the wheals join together to form larger swellings. The area of affected skin can vary in size from quite small to as large as a dinner plate. 
• Depending on the trigger, hives usually settle over hours. When there is no identifiable cause (idiopathic urticaria), hives will usually go away within a few days, but may last weeks.

Hives can look or feel unpleasant, but usually they are harmless.

Anaphylaxis

 Sometimes children have a more serious allergic reaction known as anaphylaxis. Symptoms of anaphylaxis include:

• difficulty with breathing and/or noisy breathing
• wheeze or persistent cough
• swelling of the tongue
• swelling and/or tightness in the throat
• difficulty talking or hoarse voice
• loss of consciousness and/or collapse
• becoming pale and floppy (infants/young children).

Call an ambulance immediately if your child has symptoms of anaphylaxis.

If your child has experienced anaphylactic reactions in the past, you may be advised to have an adrenaline autoinjector (e.g. an EpiPen) with you at all times. Your child could also wear a medical alert pendant or bracelet to let other people know what may cause them to have an allergic reaction. Discuss this with your GP.

Hives only, without other features described above, is not anaphylaxis. 

What causes hives?

Hives are a skin rash which can be caused by an allergic reaction, when the immune system responds to a substance such as a food or insect venom. Hives in this case commonly last for a few hours once the trigger has been removed. Hives can commonly occur without a trigger, and may be the immune system responding to a viral illness/cold. These hives commonly come and go for a few days to weeks. Hives occur when a chemical called histamine is released. 

If hives are present for over a few days with no obvious cause, allergy tests are not needed, in these cases there is generally no external trigger and the hives with gradually improve with time. Sometimes these cases may also have associated swelling of the lips/eyes.

If hives appear soon after a certain food, medicine or insect sting, and resolve within a few hours after no further exposure to this trigger, then allergy testing may be indicated.  

Care at home

Most of the time, hives as the only symptom can be safely managed at home, without the need to see a doctor. A pharmacist might provide you with some non drowsy antihistamine medication for relief of symptoms during an episode. These are safe to use from six months of age and can be used once or twice daily if needed. The best treatment for hives is to avoid the cause or trigger, however this is not always possible.

You can help treat your child’s hives by:

• avoiding known triggers for your child
• avoiding things that make the rash worse, such as sunshine, heat and hot showers
• applying cool compresses (a face washer, cloth nappy or clean tea towel soaked in cool water), which may help relieve the itching and stinging
• using non drowsy antihistamines (Cetirizine, Loratadine). 

When to see a doctor

 If your child continues to have hives for more than six weeks, take them to see your GP.

Treatment for severe or frequent hives may include:

• checking that the rash isn't caused by an underlying disorder
• medications such as corticosteroids, which can reduce the immune system's response to the triggers
• prescribing ongoing non drowsy antihistamines to provide relief from itching – these can be very useful if taken at bedtime.

If at any time the hives are associated with other symptoms (high fever, bruising, purple skin discolouration or joint pains), your child should be seen by a doctor.

If your child presents signs of anaphylaxis, then call an ambulance. 

Key points to remember

• Hives are very common and are usually harmless.
• Hives are a skin rash involving red, raised wheals that are usually very itchy.
• This type of skin rash can be an allergic reaction, which means the immune system responds to a substance as if it were toxic, but it can also have no known triggers and is the immune system responding to a viral illness.
• Treatment options include avoiding known triggers and medications such as antihistamines which can be used daily and rarely corticosteroids.
• Call an ambulance if your child has symptoms of anaphylaxis.

For more information

• Kids Health Info fact sheet: Allergic and anaphylactic reactions
• Kids Health Info fact sheet: Insect bites and stings
• See your GP.

Developed by The Royal Children's Hospital General Medicine and Dermatology departments. We acknowledge the input of RCH consumers and carers.

Reviewed October 2021.

Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit www.rchfoundation.org.au.