Urticaria

Question 1

urticaria immunologic mechanism

Answer 1

type 1 hypersensitivity reaction

Question 2

urticaria is characterized by

Answer 2

red erythemetous edematous papules and plaques

wheals surrounded by a blanchable red halo or flare (erythema)

Question 3

cardinal symptom of urticaria

Answer 3

pruritis!!

Question 4

urticaria is caused by

Answer 4

swelling of the upper dermis

individual papules and plaques last <12 hours

Question 5

acute urticaria

Answer 5

<6 weeks

Question 6

common causes of acute urticaria

Answer 6

• idiopathic
• post infection - viral, streptococcal
• food reactions - shellfish, nuts, fruit
• drug or infusion reactions

NOT detergents or contact allergens (thats type 4 hypersensitivity)

Question 7

etiology of chronic urticaria

Answer 7

> 50% idiopathic

Question 8

physical urticaria

Answer 8

(chronic)
pressure, cold, heat, water, sunlight, vibration, exercise

cholinergic urticaria - heat or emotion

Question 9

most common form of physical urticaria

Answer 9

dermatographism

Question 10

dermatographism

Answer 10

sharply localized edema or wheal within seconds to minutes after the skin has been rubbed

Question 11

immunologic urticaria

Answer 11

antigen binds to IgE on the mast cell surface causing degranulation with histamine release

histamine binds to H1 and H2 receptors to cause arteriolar dilation, venous constriction, and increased capillary permeability

Question 12

is allergy testing helpful for urticaria?

Answer 12

no

but keep diary of food or other possible triggers