urticaria

Urticaria

urticaria (also known as hives, nettle rash, or weals) is a vascular reaction of the skin (upper dermis and mucous membranes) marked by transient appearance of slightly elevated patches - wheals - which are red or pale swellings that are often attended by severe itching. Urticaria can be localised or generalised (1)
urticaria is also used to define a disease which presents with short-lived itchy weals, angio-oedema or both together (2)
- urticaria may be caused by many different factors including certain foods, drugs, infection, and emotional stress
the British Association of Dermatologists has classified utricaria according to the clinical presentation:
- ordinary urticaria
  - acute (up to 6 weeks of continuous activity)
  - chronic (6 weeks or more of continuous activity)
  - episodic (acute intermittent or recurrent activity)
- physical urticarias - repeatedly induced by the same physical stimulant
  - mechanical - delayed pressure urticaria, symptomatic dermographism
  - thermal - cholinergic urticaria, cold contact urticaria
  - other - solar urticaria, aquagenic urticaria
- angio-oedema without weals
  - idiopathic
  - drug induced
  - C1 esterase inhibitor deficiency
- contact urticaria - contact with allergens or chemical
- urticarial vasculitis - defined by vasculitis on skin biopsy
- autoinflammatory syndromes
  - hereditary
  - acquired (2)
two or more types of urticaria can occur at the same time in a patient (1)
urticaria is frequently accompanied by angioedema (3)

Reference:

Last reviewed 06/2020

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