Urticaria
Urticaria
Updated: 02/11/2021
© Jun Wang, MD, PhD
General features
- Both acute (< 6 weeks) or chronic (> 6 weeks)
- Commonly at pressure point
- Acute urticaria usually associated with infections, caterpillars and moths, foods and other allergens
- Chronic urticaria may be associated with autoimmune disorders, thyroid dysfunctions, underlying malignancy etc
Pathogenesis
- Localized mast cell degranulation
- Dermal microvascular hyperpermeability
Contraction of endothelial cells
Retraction of endothelial cells
Direct injury of endothelial cells
Endothelial injury mediated by
leukocytes
Transcytosis or vesiculovacuolar
pathway
Clinical features
- Pruritic, edematous plaques (wheals)
Pathological findings
- Dermal edema (widely spaced collagen bundles),
- Mild eosinophilic infiltrate
- Dilated lymphatics
Management
- Antihistamine, glucocorticoids, etc.
- Epinephrine if laryngeal angioedema suspected
Prognosis
- Acute urticarial
Usually resolve in 1-4 days
May progress rapidly to
life-threatening angioedema and/or anaphylactic shock
- Chronic urticaria
Variable prognosis, depending on
comorbid disease and the response to therapy
Back to acute inflammatory dermatitis
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