Medicine 6th year, Dermatology Tutorial (5th session/part three)

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September 5th, 2011

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Medicine 6th year, Dermatology Tutorial (5th session/part three)

  1. 1. Urticaria
  2. 2. Urticaria • Superficial swellings of dermis → wheals  Itchy, pale in center → pink superficial plaques, resolve over hours without a mark.  Surrounding flare is due to an axon reflex.
  3. 3. Urticaria• Deep swellings of dermis & subcutaneous & submucosal tissues → Angioedema  Painful, rather than pruritic and take longer time to resolve.• Wheals & angioedema often coexist, but may occur alone.
  4. 4. The spectrum of urticariaI. Ordinary urticaria:• Acute • Chronic (recurrent ≥6 weeks): - idiopathic (50%) - autoimmune (25-50%).II. Physical urticaria (35%) • Adrenergic urt. • Dermographism (8.5%) • Aquagenic urt. • Exercise-induced anaphylaxis • Cholinergic urt. • Localized heat urt. • Cold urt. • Solar urt. • Delayed pressure urt. • Vibratory angioedemaIII. Contact urticaria: biologic, chemical.IV. Urticarial vasculitis (proved by skin biopsy)V. Angioedema (without wheals)
  5. 5. UrticariasPotential Provoking Factors1. Drugs: penicillin, aspirin, sulfonamides, NSAIDs, ….2. Foods (eggs, fish, strawberries, milk, … etc.) & food additives (Azo dyes, benzoates, penicillin).
  6. 6. UrticariasPotential Provoking Factors (C ont.)3. Inhalants: e.g. pollen grains, house dust, feathers.4. Infections e.g. focal sepsis in tonsils, teeth or sinuses, or urinary tract infections.Recently, Helicobacter pylori has been suggested.
  7. 7. UrticariasPotential Provoking Factors (C ont.)5. Infestations: Intestinal worms.6. Emotional stress especially in cholinergic urticaria.7. Systemic disease: SLE, lymphomas, thyrotoxicosis.
  8. 8. Urticarias• Heterogeneous group of disorders.• Sudden appearance of itchy red transient wheals. Episodes of wheals “wheal come & go” for duration Less than 6 wks More than 6 wks Acute Chronic

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