Acute urticaria, which may last from several hours to several days, is often allergic in origin. However, chronic urticaria, which may last weeks or even months, is rarely allergic. It may be caused by foods, food additives, medicines, but it is almost always a "pseudo-allergy".

Symptoms:

Urticaria (Hives) may appear in several different forms, but it always includes an outbreak of pimples called "nettle rash". This rash may appear anywhere on the body and is accompanied by itching. It is characterised by red, swollen and very itchy welts that form on the skin.

There are many causes of acute urticaria:

• food allergens (eggs, fish, nuts, fruit)
  
• medicine allergens (penicillin, hormones, sulphonamides, etc.)
  
• aeroallergens (pollen, mildew, animal hair, etc.)
  
• insect stings (bees, wasps)
  
• infections (glandular fever or mono, hepatitis B. etc.)
  

In addition to allergic urticarias, there are some which are physical in origin: sun, cold, pressure.