In this section
Hives are slightly raised, red patches of skin
called wheals. They occur in groups on any part of the body
and can look like mosquito bites. They are often itchy, but
sometimes also sting. Hives are usually a sign of an allergic
reaction to things like food or insect bites. It's the bodies way
of saying it is responding or reacting to something it feels or
thinks is toxic (poisonous).
Each wheal lasts a few hours before fading
without trace. New areas may develop as old areas fade. 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
The medical word
for hives is urticaria. Hives are very common - one out of every four people
will have hives at some time in their life.
Hives will usually go away within a few days.
If your child continues to have hives for more than six weeks this
may need investigation. Treatment includes avoiding known triggers
(i.e. things known to cause the hives) and medicines. The triggers may be
different for each child.
Usually, the hives look or feel
unpleasant but are harmless. However, sometimes a more serious
allergic reaction known as anaphylactic shock can happen.
This is a medical emergency and an ambulance should be
called immediately by dialling 000.
Symptoms of anaphylactic shock
If your child has experienced anaphylactic
reactions in the past you may be advised to have ready access to
adrenaline. Your child should also wear a
Medi-alert pendant or bracelet to let other people know what may
cause them to have an allergic reaction. Discuss this with your
Often it's impossible to find out what
triggers hives in children. Usually no tests are needed. Hives are a
type of skin rash that is an allergic reaction. This means the
immune system responds to a substance as if it were toxic.
Hives occur when blood plasma leaks from the
blood vessels into the skin. This happens when a chemical called
histamine is released.
The following can cause histamine release and
The best treatment for hives is to find and
remove the cause or trigger, however this is not always possible. For most
people, each attack of hives will become more severe and intense if
they are repeatedly exposed to the same trigger.
Treatment for severe or frequent hives may
For more information or if you have any
concerns, call your GP.
Developed by the RCH General Medicine
and Dermatology Departments. First published 2003.
Reviewed November 2010.