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Urticaria
hives, nettle rash
- acute development of itchy weals / swellings in skin due to leaky dermal
vessels
Pathology
- degranulation of cutaneous mast cells
- release of histamine and inflammatory mediators
- occasionally secondary to
- viral / parasitic infection
- drug reaction - aspirin, penicillin
- food allergy
- strawberries
- food colourings
- seafood
- systemic lupus erythematosus
- physical stimuli
- heat / stress
- cold
- deep pressure
- sunlight
- water
- chemicals
Presentation
- usually child / young adults
Clinical Features
- cutaneous swellings / weals developing over few minutes
- anywhere
- last minutes to hours
- intensely itchy, no surface change or scaling
- normally erythematous, may be flesh coloured or pale
- may produce angioedema
- dermographism
Investigations
Treatment
- avoid
- oral antihistamines
Angioedema
- IV hydrocortisone
- subcutaneous adrenaline
Prognosis
- few weeks to months → spontaneous resolution
Variants
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