Itchy skin disease
- Be able to recognise acute and chronic urticaria.
- Outline initial treatment of urticaria.
- Urticaria is composed of weals: recurrent transient oedematous dermal papules and plaques, individual lesions persisting less than 24 hours.
- Weals may be asymptomatic but are often intensely itchy or sting and burn.
- Angioedema results from oedema of dermis and subcutaneous tissue.
- Urticaria may be acute (<6 weeks duration) or chronic (>3 months).
- Some acute cases are due to IgE-mediated Type 1 hypersensitivity reactions.
- Some chronic cases are due to anti-FceRI autoantibodies.
- Angioedema may rarely be due to decreased C1-esterase inhibitor.
- In many cases, no cause is found after careful history and investigation.
- Allergens include: drugs (especially antibiotics), foods (eggs, milk, peanuts, shellfish).
- Non-allergic causes include miscellaneous medical problems, infections, drugs (especially opiates, aspirin, NSAID), foods (salicylates in fruit, additives such as tartrazine, benzoates).
- Physical urticaria may be due to light touch (dermographism), pressure, heat, cold, sweat (cholinergic), water (aquagenic), sunlight (solar) or direct contact with allergens or irritants.
- Physical urticaria results in short-lasting weals (less than one hour).
- Management should include avoidance of known precipitants and antihistamines.
- Non-sedating antihistamines include loratidine, fexofenadine, cetirizine.
- Many other medications are used in unresponsive cases including H2-blockers, ketotifen, doxepin and in acute cases for a few days, oral steroids.
Read about urticaria in your textbook or online and answer the questions.
Contact urticaria testing
Idiopathic chronic urticaria