Urticaria - Itchy Skin Rash

An urticarial reaction or itchy skin rash is an allergic reaction that involves the skin. It is often associated with angioedema which is swelling of the tongue and lips.

In severe allergic cases, there may be an anaphylactic reaction which results in difficulty breathing and is life-threatening.

Most urticarial reactions do not involve the life-threatening anaphylactic reaction.

What does the urticarial skin rash look like?

The first thing that is noticed is usually intense itching. Then a red rash appears and it is often raised and can have wheals (these look white usually).

The raised red areas can be anything from a couple of millimeters to several centimeters in diameter.

The main feature of urticaria is that it is an intensely itchy skin rash.

What are the common causes of an urticarial reaction in children?

The most common cause is infection, usually a viral infection.

Food allergy (particularly peanuts, dairy products and fish) accounts for a smaller proportion of cases.

A few children get a reaction to medicines like antibiotics, or to insect stings, or parasites.

How will I know what caused the allergic reaction?

You will often know as the reaction occurs quickly (10 - 15 minutes) after the trigger. If you don't know what caused the reaction and this is the first time your child has had one, the most likely cause is an infection.

What is the treatment of an itchy skin rash (urticaria)?

The treatment is antihistamines, such as:

• loratadine (Alavert, Claritin)
• chlorpheniramine (Chlor-Trimeton, Deconamine, Rondec, Piriton)
• cetrizine (Zyrtec)

These are given for between 3 days and 2 weeks depending on response.

Steroids, such as prednisone or prednisolone, are often added to antihistamines. They are usually only given for 3 or 4 days.

Who gets urticarial rashes?

Anyone can have an allergic reaction but they often occur in children who have an atopic (allergic) tendency - this includes children who suffer from asthma, eczema and hayfever. The main feature of urticaria is it is an intensely itchy skin rash.

Does my child need skin prick tests for allergy after an urticarial rash?

This is generally not necessary after one episode.

If a food is the cause, you will often know because your child had just eaten it before the rash appeared.

Skin prick tests are useful in children who continue to get urticarial reactions if a food is thought to be the culprit.

Does my child need Epinephrine (Adrenaline) at home?

If your child had an anaphylactic reaction which caused difficulty breathing or shock, she will require Epinephrine (Adrenaline) in an injectable pen at home.

If your child just had urticaria or angioedema (swelling of the tongue or lips), she will not need Epinephrine (Adrenaline) at home.

You need to discuss this with the doctor who saw your child when she was unwell.

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