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Pruritic, elevated skin lesions surrounded by erythematous base commonly described as "hives"
Due to transient extravasation of plasma into the dermis. It is a common condition - 25% of individuals will have it at some stage.
Deeper subcutaneous extension is much less common and termed angioedema. It involves face (eyelids, lips, tongue), hands and feet, and sometimes other areas ( trunk, genitalia, mucous membranes ).
Acute Urticaria (
<6 weeks) Chronic Urticaria (>6 weeks)
Explore events a few hours or days before onset of rash.
A specific cause is not identified in most of the cases (Idiopathic)
Other causes are
Erythematous raised skin lesion (Wheal)
is a medical emergency - sudden onset of urticaria, angioedema, dyspnoea or hypotension . Treat immediately
If recurrent angioedema without wheals, think of
C1 esterase inhibitor
Blotchy rash typical of urticaria
Urticarial lesions with typical clear skin in centre.
These are not "target lesions"
How to distinguish? EM is:
Investigations are usually not indicated for acute urticaria
Initial investigations of chronic urticaria include FBE, Differential, ESR and ANA.
Indications for specialist referral:
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