DERMATOLOGY
Etiology
Allergens (foods, drugs, insect stings)
Infections
Physical triggers (cold, pressure)
Autoimmune (chronic urticaria)
Pathogenesis
Histamine release from mast cells → vasodilation + leakage → wheals
Clinical Features
Transient pruritic wheals
Angioedema may accompany
Lesions last <24 hours each
Treatment
Oral antihistamines (H1 blockers)
Avoid triggers
Steroids for short severe flares
Omalizumab for chronic refractory urticaria