Clinical Features:

• Defined as urticaria that persist for longer than 6 weeks
• Most common in middle-aged individuals
• Caused in some cases by IgG autoantibodies which cross-link IgE receptors on basophils and mast cells, causing their degranulation
• Some cases are associated with allergies, especially to foods or aspirin.
• Other cases are secondary to cholinergic urticaria, caused by an increase in body temperature following exercise, overheating or stress.

Histologic Features (similar to what is seen in acute urticaria):

• Dermal edema
• Vascular dilatation and endothelial swelling
• Scant perivascular infiltrate of lymphocytes, eosinophils and neutrophils
• Interstitial neutrophils and mast cells

Cases associated with this book:

Chronic urticaria
Author: Artur Zembowicz M.D. Ph.D.

Conference: Dermpedia Teaching Collection