Urticaria, Angioedema, Anapylaxis (Fasano)

Question 1

common disorder affecting up to 20% of the population, that may or may not be accompanied by angioedema; key features: pruritic, transient and non-scarring!

Answer 1

urticaria

Question 2

Which of these is NOT a distinguishing feature of chronic utricaria?

A. Symptoms almost daily for >4 weeks

B. It represents the minority of cases of urticaria

C. It is often associated with histamine-mediated angioedema

D. Usually a cause cannot be determined

E. The lesions of chronic urticaria look and feel the same as those of acute urticaria

Answer 2

A.

Symptoms must occur almost daily for at least 6 weeks to be considered chronic urticaria.

Question 3

Degranulation of _____ cells results in the release of histamine and other vasoactive mediators, which induce the immediate hypersensitivity response

Answer 3

mast

Question 4

Which of the following statements regarding mast cells is FALSE?

A. They are present in bone marrow, skin and mucosal epithelial cells

B. They contain histamine, tryptase and leukotrienes, all of which are potent vasodilators

C. They have high affinity receptors for IgG

D. They are key players for both acute and chronic urticaria

E. They release substances that provoke smooth muscle contraction, leading to the leakage of fluid into the tissues

Answer 4

C.

Mast cells contain high affinity receptors for IgE, which binds readily to their surface. When allergens bind to IgE on the mast cell surface, it triggers the release of the mast cell’s contents, which include a variety of vasoactive substances that cause vasodilation, erythema, and increased vascular permeability.

*mast cells can also be triggered directly by complement factors (c3a, c4a, c5a), which bind to their receptors on the mast cell surface

Question 5

Certain drugs may directly induce mast cell activation and acute urticaria. Which of the following drugs is associated with “red man syndrome”, in which nonspecific degranulation of mast cells leads to widespread erythema and rash?

A. Opiates

B. Narcotics

C. Muscle relaxants

D. Vancomycin

E. Radioconrast media

Answer 5

D

All the others listed may cause mast cell degranulation but vanco infused too quickly is associated with red man syndrome.

Question 6

What is the triple response of Lewis and how does each of the responses occur?

Answer 6

1. Erythema from localized capillary dilatation
2. Flare from neighboring aretriolar dilatation (due to a nerve impulse reflex)
3. Edema from increased vascular permability, due to vasoactive substances released by mast cells

Question 7

a physical urticaria diagnosed by observing a patient’s skin 5 min after they have drawn on it with a tongue depressor

Answer 7

dermatographism

Question 8

a physical urticaria that is more painful than itchy, and shows delayed erythema and edema with lesions that are slow to resolve

Answer 8

pressure urticaria

Question 9

this type of urticaria constitutes 30% of the physical urticarias and is more common in teenagers and young adults; may be associated with lacrimation, salivation, diarrhea, and wheezing

Answer 9

cholinergic (heat) urticaria

Question 10

Which of the following is not a type of chronic urticaria?

A. Pressure urticaria

B. Heat urticaria

C. Complement-associated urticaria

D. Autoimmune urticaria

E. Idiopathic urticaria

Answer 10

C.

This is a form of acute urticaria that is often associated with a viral infection.

Question 11

What is the pathogenesis of autoimmune urticaria?

Answer 11

usually it is due to IgG autoantibodies that form against the IgE receptors on mast cells. The binding of these autoantibodies stimulates the mast cells to release their contents.

Question 12

this medication binds to free circulating IgE, preventing it from binding to the mast cell and leading to decreased B cell production of IgE and downregulation of its receptor

Answer 12

omalizumab

Question 13

swelling that is painful and burning, not itchy, and is due to fluid extravasation in the deep dermis and subQ tissue

Answer 13

angioedema

*may involve the face, tongue, extremities, genitalia or GI tract

Question 14

autosomal dominant disorder caused by mutations in the c1-inhibitor gene leading to overactivation of complement and presents as recurrent episodes of angioedema without hives

Answer 14

hereditary angioedema

*angioedema caused by bradykinin - NOT associated with hives, anaphylaxis or histamine

Question 15

type I or type II hereditary angioedema results from a mutation that decreases C1 inhibitor, leading to both decreased C1 inhibitor levels and function

Answer 15

type I hereditary angioedema

Question 16

type I or type II hereditary angioedema results from synthesis of a mutated C1 inhibitor, leading to decreased C1 inhibitor function, while their levels stay normal

Answer 16

type II hereditary angioedema

Question 17

bradykinin-induced angioedema that is due to malignancy, or autoantibodies against the C1 inhibitor

Answer 17

acquired angioedema

Question 18

Which of these is not a treatment option for hereditary angioedema approved by the FDA?

A. IV infusion of C2 inhibitor concentrate purified from human plasma

B. Subcutaneous injection of a kallikrein inhibitor

C. ACE inhibitor therapy to reduce circulating bradykinin

D. Subcutaneous injection of a bradykinin receptor antagonist

Answer 18

C

ACE inhibitors and bradykinin can form a complex, causing BK-induced angioedema.

Question 19

Hallmark feature of bradykinin-induced angioedema?

Answer 19

recurrent episodes of painful swelling without hives

Question 20

In the Gel & Coombs classification, anaphylaxis is a:

A. Type I reaction

B. Type II reaction

C. Type III reaction

D. Type IV reaction

Answer 20

A

Mechanism of anaphylaxis: rapid release of mast cell mediators ⇒ urticaria, angioedema, hypotension ⇒ incr. vascular permeability ⇒ shifts 50% of vascular volume to extracellular space within 10 min ⇒ hypotension & shock

Question 21

treatment for anaphylaxis

Answer 21

IM epinephrine!

Question 22

an elevated baseline level of this enzyme has been found to be associated with more severe allergic/anaphylactic reactions to insect venoms

Answer 22

tryptase (serine protease released from activated mast cells)

Question 23

Which of these is not a treatment associated with chronic urticaria?

A. H1 blockers

B. H2 blockers

C. Leukotriene receptor antagonists

D. Anti-IgE monoclonal antibody treatment

E. ACE inhibitors

Answer 23

E