Urticaria

• What is urticaria?


  Commonly referred to as hives

  Local/generalised superficial swelling of the skin

  
• Angio-oedema is a deeper form of urticaria with swelling in dermis & submucosal or subcutaneous tissues.
• What are the RFs of urticaria?


  Allergens (foods, meds, insect stings)

  Physical stimuli (pressure, cold, heat)

  Infections (viral or bacterial)

  Autoimmune processes

  Stress & emotional factors

  Genetics -> may have predisposition
• Pathophys - urticaria


  Release of histamine or other mediators from mast cells & basophils -> increased vascular permeability & formation of wheals
• What are the signs & symptoms of urticaria?


  Pruritus (itching), often intense

  Erythematous wheal with well-defined borders

  Wheals (vary in size & shape)

  Rapid onset & resolution (usually within 24 hrs)

  Angioedema (swelling of deeper tissues) -> can involve lips, eyelids or extremities
• What are the DDx of urticaria?


  Angioedema without wheals

  Dermatitis (contact dermatitis, atopic dermatitis)

  Drug eruptions

  Erythema multiforme

  Vasculitis (consider if urticaria lesions remain > 24hrs & are painful, non-blanching & palpable - esp if systemic symptoms)

  Autoimmune disorders (SLE)
• What are the Inx of urticaria?


  Obs

  Full Hx & examination

  Allergy testing

  Urinalysis

  Bloods (FBC, LFTs, TFTs, CRP)

  Skin biopsy
• What are the possible complications of urticaria?


  Resp compromise in severe cases of angioedema involving upper airway

  Psychological distress & decreased QoL -> due to chronic or recurrent symptoms

  Side effects from long-term medication use
• What is the management of urticaria?


  Identification & removal of triggers

  Pharmacological treatment

  • Non-sedating antihistamines (cetirizine, loratadine; H2-receptor antagonists) -> can be given for up to 6 weeks in acute episode, or longer (3-6 months)
  • LTRAs or omalizumab
  • Oral corticosteroid (prednisolone 40mg, for 7 days)
  • Antipruritic creams (calamine lotion or topical menthol 1% aqueous cream)

  Patient education

  Regular follow up
• What are the different types of urticaria?


  Acute (symptoms < 6 weeks)

  Chronic (symptoms > 6 weeks)
• When should pts with urticaria be referred to dermatology?


  Ppl w/ urticaria that is painful and persistent (suspect vasculitic urticaria)

  Ppl whose symptoms not well controlled on antihistamine treatment

  Ppl w/ angio-oedema & no wheals that do not respond to (1st line)

  Ppl w/ acute severe urticaria thought to be due to a food or latex allergy

  Ppl with forms of chronic inducible urticaria that may be difficult to manage in primary care (e.g. solar or cold urticaria)
• What is shown in the image?

  Urticarial rash