Acute urticaria is defined as the presence of evanescent

Evanescent

Evanescent may refer to:* Evanescent , a class of skin lesions* "Evanescent" , a song by Vamps* Evanescent wave, a term applied to electromagnetic waves that decay exponentially...

 wheals which completely resolve within six weeks.

Acute urticaria becomes evident a few minutes after the person has been exposed to an allergen. The outbreak of acute urticaria may last several weeks, but usually the hives are gone in six weeks. Typically, the hives are a reaction to food, but in approximately half the cases the trigger is unknown. Common foods may be the cause, as well as bee or wasp stings, or skin contact with certain fragrances.

See also

• Wheal
  Wheal
  Wheal may refer to:*Wheal response, a cutaneous condition left by a blow or as part of an allergic reaction*Wheal, a Cornish mine...
  
  
• Urticaria
  Urticaria
  Urticaria is a kind of skin rash notable for pale red, raised, itchy bumps. Hives is frequently caused by allergic reactions; however, there are many non-allergic causes...
  
  
• Chronic urticaria
  Chronic urticaria
  Chronic urticaria is defined as the presence of evanescent wheals which persist for greater than six weeks....
  
  
• Skin lesion
• List of cutaneous conditions