Urticaria And Angioedema

Question 1

What is urticaria?

Answer 1

Erythematous, edematous wheals
Blanch with pressure
Symmetric distribution 
Very pruritic
Usually last less than 4 hours but can last 24-48 hours

Question 2

What is angioedema?

Answer 2

Well demarcated non pitting edema
Reaction in deeper tissues
Begin as tingling/pain
Non pruritic
May cause life threatening respiratory distress

Question 3

What are the characteristics of acute urticaria?

Answer 3

Last less than 6 weeks
More common in younger population
Lesions are intensely pruritic
May or may not be accompanied by angioedema
More likely to find cause compare to chronic urticaria

Question 4

What are the characteristics of chronic urticaria?

Answer 4

Last longer than 6 weeks
The longer the hives present the least likely to find cause
More common in adults than in children

Question 5

What are some causes of chronic urticaria?

Answer 5

Autoimmune
Physical urticaria (cold, heat, solar, pressure)
Urticarial vasculitis- hives longer than 24 hours leaving bruise
Autologous serum challenge

Question 6

How to manage urticaria?

Answer 6

Avoidance
H1 and H2 antihistamines combined
No H2 antihistamines alone can worsens hives
Corticosteroids- avoid chronic use

Question 7

What are the areas most commonly affected by angioedema?

Answer 7

Face
Tongue
Lips
Eyelids

Question 8

What is the most common exogenous cause of angioedema?

Answer 8

ACE induced angioedema
No associated urticaria
May cause swelling of tongue, pharynx or larynx
May require intubation or tracheostomy acutely
Treated by stopping ACEI

Question 9

What is the clinical presentation of hereditary angioedema (HAE)?

Answer 9

Usually manifest in 2nd decade
Edema may develop in 1 or several organs
Attacks last 2-5 days before spontaneous resolution

Question 10

What is the most common cause of mortality in HAE?

Answer 10

Laryngeal edema

Death may occur in those with no previous laryngeal edema episodes

Question 11

What are the 3 types of HAE C1 INH deficiency?

Answer 11

Type 1- plasma levels of C1 INH reduced
Type 2- normal level of C1 INH but defective
Type 3- estrogen related, no changes in complement

Question 12

What is the genetics of HAE?

Answer 12

Autosomal dominant

All patients are heterozygous

Question 13

How to diagnose HAE?

Answer 13

Clinical presentation 
C4 level persistently low even between attacks
C4 low—-> further workup
C4 normal -> DDX
C1INH quantitative and qualitative
C4 and C2 reduced in acute attack
C1q normal

Question 14

How to manage HAE?

Answer 14

C1 esterase inhibitor prophylaxis and in acute attack
Intubation and respiratory support in case of laryngeal edema
If C1 inhibitor concentrate not available fresh frozen plasma can be used

Question 15

What is acquired C1 inhibitor deficiency?

Answer 15

Caused by massive amounts of immune complex which activates C1 so that C1 inhibitor is depleted
C1q levels distinguish AAE from HAE

Question 16

What are the characteristics of idiopathic angioedema?

Answer 16

Recurrent angioedema, 
No recognized exogenous precipitant
Normal C4 levels
Unassociated with concomitant urticaria
Sub types might or might not respond to antihistamines

Question 17

What is the treatment for acute episodes of angioedema?

Answer 17

C1INH concentrate
Diphenhydramine (50mg)- repeat in 4h
Prednisone
Epinephrine if rapidly advancing
H2 antihistamines