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Urticaria

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WHAT IS IT?

Abstract

VOL: 99, ISSUE: 40, PAGE NO: 23

 

WHAT IS IT?
- The word urticaria comes from the Latin for ‘nettle’ and refers to a group of disorders in which swellings (weals) occur on the skin. It is also known as hives.

 


 

- These can be a few millimetres or several centimetres in diameter. They can be white or red, are often surrounded by a red flare and are frequently itchy.

 


 

- They can last a few minutes or several hours, and may change shape. In chronic urticaria recurrent rashes can last in excess of six weeks.

 


 

- Angioedema is a deeper form of urticaria frequently occurring in the eyelids, lips and sometimes in the mouth. The swellings may not be itchy and usually settle in a few days.

 


 

- Urticaria is common, affecting 20 per cent of people at some stage of their lives.

 


 

TYPES OF URTICARIA
- Acute urticaria can be caused by foods, colourings, preservatives or by medicines, especially aspirin, antibiotics, and codeine. Other possible causes are plant, animal and chemical contacts, for example latex.

 


 

- The cause of chronic urticaria, which can last in excess of six weeks, is rarely established.

 


 

CLASSIFICATION
- Cholinergic urticaria - occurs under conditions that cause sweating such as heat, exertion and stress.

 


 

- Dermographism - itching weals occur when skin is rubbed. Weals often appear as lines.

 


 

- Cold urticaria - cold, including rain and wind, causes itching weals.

 


 

- Solar urticaria - itching weals occur immediately after exposure to sunlight (very rare).

 


 

- Aquagenic urticaria - small weals occur on the skin at sites of contact with water of any temperature (extremely rare).

 


 

- Delayed pressure urticaria - swellings occur at skin sites where pressure has been applied (tight clothes, gripping tools, and so on).

 


 

- Angioedema urticaria - deep-seated subcutaneous swellings occur with or without mucous membrane and are not itchy.

 


 

- Urticarial vasculitis - a small percentage of people experience tender weals that last longer than two days and can bruise. These symptoms can be accompanied by Joint and stomach pains as a result of inflamed blood vessels (vasculitis).

 


 

CAUSES
The release of histamine and other chemotactic agents causes small blood vessels to leak, which results in tissue swelling. This can be triggered by:

 


 

- Foods;

 


 

- Colourings and preservatives;

 


 

- Perfumes;

 


 

- Flowers and plants;

 


 

- Parasites;

 


 

- Blood transfusions;

 


 

- Dyes;

 


 

- Heat and cold;

 


 

- Water;

 


 

- Sunlight;

 


 

- Exercise;

 


 

- Pressure on the skin;

 


 

- Drugs: antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs).

 


 

FIRST LINE TREATMENT
- It is important to avoid anything that may worsen urticaria.

 


 

- Antihistamines block the effects of histamine and can help reduce itching and rash in most people, but may not relieve urticaria completely.

 


 

SECOND LINE TREATMENT
- Doxepin.

 


 

- Prednisolone - useful for severe angioedema. Should never be used routinely.

 


 

- Cyclosporin - for chronic idiopathic urticaria under specialist supervision.

 


 

- Leucotriene antagonists.

 


 

- Exclusion diets - selected patients only. Strict monitoring required by specialist and dietitian.

 


 

FURTHER INFORMATION
Johnson, G., et al (2000) The Minor Illness Manual. Abingdon: Radcliffe Medical Press.

 


 

WEBSITES
NHS Direct

 


 

USEFUL CONTACTS
Medic Alert Foundation 1 Bridge Wharf, 156 Caledonian Road, London N1 9UU. Tel: 020 7833 3034.

 


 

British Allergy Foundation St Bartholomew’s Hospital, West Smithfield, London EC1A 7BE. Tel: 020 7600 6127.
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