Urticaria

Acute urticaria

Patients present with sudden onset of very itchy, transient wheals which resolve in under 24 hours. May be accompanied by angioedema.

Chronic urticaria

Regular episodes persisting for more than 6 weeks, fluctuating in intensity. There may be associated dermographism. Spontaneous resolution can take months or years.

Dermographism

Angioedema

Subcutaneous swelling with or without rash.

Most patients with urticaria can be managed in Primary Care.

Stop any histamine releasing drugs, e.g. aspirin, codeine, ACE inhibitors, penicillin, non-steroidal anti-inflammatory drugs.

Causes of acute urticaria:

Detailed history may identify possible triggers e.g. medication Laboratory tests (IgE) are rarely necessary and only to confirm suspected specific triggers

SKIN PATCH TESTING IS INAPPROPRIATE

Treatment of acute urticaria: :

• Non-sedating antihistamines
• Sedating antihistamines: additionally at night if sleep disturbed
• Continue regular treatment until symptoms subside

Causes of chronic urticaria:

• Idiopathic
• Physical e.g. cold, pressure, dermographism
• Auto-immune aetiology

Treatment of chronic urticaria:

• Non-sedating antihistamines daily for 6 months
• Sedating antihistamines: additionally at night if sleep disturbed
• Topical antipruritic: 1% menthol in aqueous cream

Causes of angioedema:

• ACE inhibitors
• Idiopathic
• C1 esterase inhibitor deficiency is rare and specific treatment is required

Investigation of angioedema without urticaria:

• Check complement levels

Treatment of angioedema:

• Stop ACE inhibitor

Non-sedating antihistamines

• Persistent urticaria / angioedema unresponsive to 3 different antihistamines each for 4–6 weeks.
• Urticarial vasculitis with associated joint pains, persistent wheals (more than 24 hours) and bruising.