Urticaria is common and affects 20% of people at some stage of their lives. Angio-oedema is mediated by histamine and often develops in people suffering from urticaria but it may appear on its own.

Histamine release can be triggered by exercise, pressure on the skin and other physical factors as well as foods, drugs and infections.

Often no cause can be found but sometimes it may be caused by an infection. Almost any medicine can cause an acute attack, but antibiotics (especially penicillins) and aspirin are commonly responsible. Sometimes foods may be responsible including nuts, fish, eggs, milk, tomatoes, vegetables and berries.

There is a hereditary tendancy to angio-oedema.

Histamine is released from the skin and causes itching, redness and swelling.

Weals occur anywhere on the body at any time.

In acute angioedema a bout of urticaria usually lasts a few days only.

There is no special test that can reliably identify the cause, but some may be done if your history suggests an underlying cause.

If an allergic reaction to food is strongly suspected a skin test or a specific blood test may be performed by a specialist in skin or allergic diseases.

In a small percentage of people foods, colouring agents and preservatives appear to cause the condition. A food diary can be kept, and then these substances can be left out of the diet to see if the condition improves and then later deliberately reintroduced.

It is important to avoid anything that may cause the angio-oedema such as heat, alcohol, aspirin and aspirin containing compounds (paracetamol does not usually cause a problem). Foods, colouring agents and preservatives can be avoided in the rare instances where these have proved to be a problem.

Antihistamines block the effects of histamine and reduce itching and rash in most people, but may not relieve the symptoms completely. It maybe necessary to take antihistamines regularly.

A related type of antihistamine usually used for stomach ulcers can be added to the histamines used to treat the skin.

If antihistamine tablets are not helpful you can discuss this with your doctor who may arrange for further tests and try other medicines.

Steroids may occasionally be given for a short while for severe flare ups.

Tongue or throat swelling is an unusual, but alarming sign of angio-oedema which is rarely life threatening except in acute food allergies and the rare hereditary form of angio-oedema. Sprays or even injections of adrenaline (which can be self-administered) often provide rapid relief.

You will not need regular check-ups although you should attend the hospital urgently if you suffer from difficulty breathing, wheezing or dizziness as a result of an attack.