Chronic Spontaneous Urticaria and Angioedema

What are the aims of this leaflet?
The leaflet has been written to help you understand more about urticaria and angioedema.  It tells you what they are, what causes them, what you can do about them, and where you can find out more about them.  The first part of this leaflet deals mainly with ordinary urticaria and angioedema – the most common form.

What are urticaria and angioedema?

• Urticaria is common, and affects about 20% of people at some stage of their lives.  It is also known as hives, nettle rash, or welts.  The short-lived swellings of urticaria are known as weals (see below).

• Angioedema is a deeper form of urticaria.

An affected individual may have urticaria alone, or angioedema alone, or both together.  The most common form is called ‘ordinary urticaria’, which is usually divided into ‘acute’ and ‘chronic’ forms.  In ‘acute’ urticaria/angioedema, the bout lasts from a few days up to six weeks. Chronic urticaria, by definition, lasts for more than six weeks.

What causes urticaria and angioedema?

Urticaria is caused by the release of histamine from mast cells (allergy cells) within the skin.  Angioedema is caused by release of chemical similar to histamine called bradykinin.  This can be triggered in many ways, for example by exercise, by pressure on the skin, and by other physical factors as well as by foods, drugs and infections. However in the common ‘ordinary’ form of urticaria and angioedema, it is unusual for an external cause to be identified. In some patients with ordinary chronic urticaria, the release of histamine from skin mast cells is triggered by factors circulating in the blood, such as antibodies directed against their own mast cells – a process known as autoimmunity. Tests for this are not routinely available, and generally do not alter the treatments used.  This seems to be the commonest cause for urticaria and angioedema in most patients.

What are the symptoms of urticaria and angioedema?

The main symptom of urticaria is itching: angioedema, however, may not be itchy.  Although urticaria can be distressing, because of itching and its appearance, it has no direct effect on general health.

Are urticaria and angioedema hereditary?

The ‘ordinary’ common type of urticaria and angioedema is not hereditary.

What do ordinary urticaria and angioedema look like?

The weals of urticaria may be pale, pink or red, and may look like nettle stings.  They can be different shapes and sizes; often they are surrounded by a red flare.  They are usually itchy.  As the raised weals flatten, they leave red marks that usually disappear in a day.  New weals may then appear in other areas.  In ordinary urticaria the weals can occur anywhere on the body, at any time, and usually fade within a day.

The pale or pink, deeper swellings of angioedema occur most frequently in the eyelids, lips and sometimes in the mouth. They may not be itchy, and usually settle in a few days. If the hands are affected, they may feel tight and painful.

How will ordinary urticaria be diagnosed?

Usually its appearance, or a description of it, will be enough for your doctor to make the diagnosis.  In the vast majority of people no cause can be found, though your doctor will ask you questions to try to identify one. There is no special test that can reliably identify the cause of urticaria, but some tests may be done if your answers suggest an underlying cause.

• In chronic urticaria, it is rare for allergy to be the cause, so routine allergy tests such as skin prick tests or specific IgE (RAST test) are not necessary. In a small percentage of people, foods containing large quantities of salicylates, colouring agents (azo dyes) and preservatives appear to worsen the urticaria. A food diary can then be kept: these substances can be left out of the diet to see if the condition improves, and later deliberately reintroduced. However, as urticaria is such a variable disease, the interpretation of these elimination diets is difficult.  Sometimes normal cycles such as menstrual cycles and psychological stress can exacerbate attacks.

Can ordinary urticaria and angioedema be cured?

The treatments outlined below suppress the condition rather than cure it.  In half of the people with chronic ordinary urticaria, the rash lasts for 6-12 months, and then gradually disappears. It usually does not return. However in any one individual the course of urticaria is unpredictable.

What is the treatment for ordinary urticaria?

• It is important to avoid anything that may worsen urticaria.  These are listed below in detail under the heading ‘What can I do?’
• Antihistamines block the effect of histamine, and reduce itching and the rash in most people, but may not relieve urticaria completely. If urticaria occurs frequently, it is best to take antihistamines regularly. There are many different types. The older ones often cause drowsiness. The newer ones are much less likely to cause drowsiness, but may do so if taken with alcohol. No particular antihistamine is best for everyone, so your doctor may need to try different ones to find the one that suits you best. Antihistamine tablets may need to be taken for as long as the urticaria persists. Reports of serious side effects are rare, but occasionally a few cause weight gain, and some should not be taken at the same time as particular medicines.
• A related type of antihistamine (e.g. Cimetidine and ranitidine), which is usually used to treat stomach ulcers, can be added to the standard antihistamines used to treat the skin.
• If antihistamine tablets are not helpful you can discuss this with your doctor who may arrange further tests, and try other medicines. Some of these may not be licensed for urticaria, but can be useful treatments.
• Oral steroids may occasionally be given briefly for severe flares of acute and chronic urticaria, but generally are not necessary.
• New treatments that act by suppressing the immune system (e.g. Ciclosporin) are being used in a few of the most severely affected people in specialist skin and allergy centres, and may be beneficial.
• Tongue or throat swelling is an unusual but alarming sign of angioedema, which is rarely life threatening in this type of angioedema unlike in acute food or medicine allergies and the rare hereditary form of angioedema called C1 inhibitor deficiency. Injections of adrenaline (epinephrine) are generally not required for this type of angioedema.

What can I do?

It is important to avoid anything that may worsen urticaria – such as sudden changes in temperature, tight clothes, alcohol, aspirin and aspirin containing compounds, and if possible other similar medicines such as Nurofen (paracetamol does not usually cause a problem). Medicines called ACE inhibitors (often used to treat high blood pressure) should be avoided, especially if angioedema is present. Foods, containing large amount of salicylates, preservatives such as benzoates and food colouring in particular azo dyes can aggravate urticaria in some individuals.