Chronic urticaria is a condition where an itchy rash persists 'on and
off' for six weeks or more. The cause of the rash is often not clear.
Many people also develop swelling of the lips, tongue or other areas of
the body from time to time. The symptoms can often be eased with
antihistamine tablets.
What is chronic urticaria?
Urticaria
(sometimes called hives) is an itchy rash caused by tiny amounts of
fluid that leak from blood vessels just under the skin surface.
Urticaria is classed as:
- Acute urticaria - if it develops
suddenly and lasts less than six weeks. Most cases last 24-48 hours.
About 1 in 6 people will have at least one bout of urticaria in their
life. It can affect anyone at any age. Some people have recurring bouts
of acute urticaria.
- Chronic urticaria - if it persists long-term. Chronic means
persistent or ongoing. In chronic urticaria a rash develops on most
days for at least six weeks. This is uncommon. About 1 in 1000 people
develop chronic urticaria at some stage in their life. It is twice as
common in women than men. Some people have an urticarial rash 'on and
off' for months, or even years.
The rest of this leaflet deals only with chronic urticaria. See separate leaflet for information about acute urticaria.
What does the rash of urticaria look like?
The
rash can affect any area of skin. Small raised areas called weals
develop on the skin. The weals look like mild blisters and are itchy.
Each weal is white or red and is usually surrounded by a small red area
of skin which is called a flare. The weals are commonly 1-2 cm across
but can vary in size. There may be just a few but sometimes many
develop over various parts of the body. Sometimes weals that are next
to each other join together to form larger ones. The weals can be any
shape but are often circular.
As a weal fades, the surrounding
flare remains for a while. This makes the affected area of skin look
blotchy and red. The blotches then fade gradually and the skin returns
to normal. Each weal usually lasts less than 24 hours. However, as some
fade away, others may appear. It can then seem as if the rash is moving
around the body. The rash may clear completely only to return a few
hours or days later.
Are there any other symptoms?
- The appearance of the rash and the itch can cause distress.
- A related condition called angio-oedema occurs from time to time in
about half of people with chronic urticaria. In this condition some
fluid also leaks into deeper tissues under the skin which causes the
tissues to swell.
- The swelling of angio-oedema can occur anywhere in the body but most commonly affects the eyelids, lips and genitals.
- Sometimes the tongue and throat are affected and become swollen.
The swelling sometimes becomes bad enough to cause difficulty breathing.
- Symptoms of angio-oedema tend to last longer than urticarial weals.
It may take up to three days for the swollen areas to subside and go.
- A variation called 'vasculitic urticaria' occurs in a
small number of cases. In this condition the weals last more than 24
hours, they are often painful, may become dark red, and may leave a red
pigmented mark on the skin when the weal goes.
What causes chronic urticaria?
A
'trigger' is thought to cause the release of chemicals (such as
histamine) from cells in the skin. The chemicals cause fluid to leak
from tiny blood vessels under the skin surface. The fluid pools to form
weals. The chemicals also cause the blood vessels to open wide (dilate)
which causes the flare around the weals. The trigger is not known or identified in many cases. Possible causes in some cases include the following:
- In
up to a third of cases the cause may be an 'auto-immune' problem.
Auto-immune means that the body's antibodies cause disease. Antibodies
normally fight off germs (viruses and bacteria). In some people, one
type of antibody attaches to cells under the skin and causes them to
release histamine and other chemicals. The reason why this happens is
not clear.
- An allergy to a food, medicine or parasite (such as worms in the
gut) is an uncommon cause of chronic urticaria. A skin specialist may
advise tests if an allergy is suspected.
- Physical urticaria. This is when a localised rash appears when the
the skin is physically stimulated. The most common is called
dermographism when a rash develops over areas of skin which are firmly
stroked. Sometimes an urticarial rash is caused by heat, cold, emotion,
exercise, or strong sunlight. See separate leaflet called 'Physical Urticarias'. This kind of urticaria often causes bouts of acute symptoms, but sometimes causes persistent chronic symptoms.
- A germ called H. Pylori which is commonly found in the
stomach may be a factor in some cases. If you are infected with this
germ and it is cleared with treatment, it may cure the problem with
urticaria.
Is chronic urticaria serious?
The rash is
usually itchy. Each weal usually lasts less than 24 hours. However, as
the rash may constantly come and go, the ongoing itch may cause
distress and difficulty sleeping. Bouts of angio-oedema which occur
from time to time in about half of people with chronic urticaria can
sometimes cause serious breathing difficulties.
What is the course and outcome (prognosis) of chronic urticaria?
Chronic
urticaria tends to 'come and go'. You may have times when the rash
appears on most days, and then times when the rash may go away for a
while. The severity of the rash and itch varies from person to person.
Some things such as heat, cold, menstrual periods, stress, or emotion
may make the rash flare up worse than usual.
- Symptoms may go away completely after a few months, but the condition lasts several years in some cases.
- In about half of cases, symptoms go within 3-5 years after it first starts.
- In about 1 in 5 cases the symptoms persist 'on and off' for more than 10 years.
What are the treatments for chronic urticaria?
Antihistamine tablets
The release of
histamine under the skin is involved in causing the rash of urticaria.
Antihistamines block the action of the histamine. Most affected people
have at least partial relief, and sometimes total relief of their
symptoms with antihistamines. There are various antihistamines.
- Some older ones tend to cause drowsiness, but may be useful to take at bedtime.
- Modern antihistamines are less likely to cause drowsiness. If needed, you can take them regularly.
- Some people take an older 'sedating' antihistamine at bedtime, and a modern 'non-sedating' one during the daytime.
- Some people respond to one antihistamine better than another. If
one antihistamine has not helped much, a different one may suit better.
It is usually worth trying an antihistamine for 1-2 weeks before
deciding if it is helping or not.
- Some people take antihistamines 'as required' when symptoms flare
up. However, if the rash usually develops on three or more days each
week, it is best to take the antihistamine every day whether the rash
is present or not. This is to prevent the rash and itch from developing rather than taking medication 'now and then' in response to a rash that develops.
Soothing the rash
Creams such menthol in
aqueous cream are useful to cool the skin and help to relieve itch. A
tepid bath or shower may relieve the itch before bedtime and help you
to sleep.
Avoiding triggers or aggravating factors
Occasionally
a 'trigger' such as a food is identified which causes the rash. You may
then be able to avoid it. However, it is unusual to identify a trigger.
For example, if a food trigger is suspected, then you may be asked to
keep a food diary to try and identify which food is responsible.
Various
other factors may make symptoms worse (but are not the main 'trigger').
The following are things that some people have found helpful, but there
is little proof that they work in everybody.
- Try avoiding
tight clothes as weals sometimes tend to occur at sites of local
pressure. For example, under belts, under tight fitting shoes, etc.
- Try keeping cool as urticaria may tend to flare up in warmer conditions. In particular, keep the bedroom cool at night.
- Some things worth considering include: alcohol, hot baths, strong
sunlight, undue emotion. If you think these are making symptoms worse
then it may be helpful to avoid them.
- See a doctor if you think a medicine is making symptoms worse as a
change in medication may be an option. Some medicines worth considering
include: aspirin, anti-inflammatory painkillers, codeine, ACE
inhibitors.
Steroid tablets
Steroids reduce inflammation
and may ease urticaria. However, it is not a usual treatment due to the
serious side-effects which are likely to occur if you take steroids
regularly. However, a short course of steroids may be advised
occasionally for a bad flare-up of symptoms.
Other treatments
Various other treatments have been tried with variable success. One may be advised by a specialist. For example:
- Strict diets which avoid possible food triggers.
- Immunosuppressant therapy (but there is a risk of serious side-effects).
- Other medicines which have limited evidence of working in most cases, but may work in a few cases.
- If relevant, clearing H pylori infection of the gut. (See separate leaflet called 'H Pylori and Stomach Pains'.)
Treatment of associated angio-oedema
Antihistamines
usually help to reduce the swelling of angio-oedema. Occasionally, an
adrenaline injection and emergency hospital treatment is necessary if
the swelling affects the throat and breathing becomes difficult.
Disclaimer: This article is for information only and should not
be used for the diagnosis or treatment of medical conditions. EMIS and
PiP have used all reasonable care in compiling the information but make
no warranty as to its accuracy. Consult a doctor or other health care
professional for diagnosis and treatment of medical conditions.
© EMIS and PiP 2008 Reviewed: 26 Aug 2008
