Urticaria and Angioedema

Question 1

3 typical features of urticaria

Answer 1

• central swelling
• pruritus or burning sensation
• fleeting nature (returns to normal in 1-24 hrs)

Question 2

what is angioedema

Answer 2

• sudden swelling of lower dermis and subcutis
• painiful > itchy
• sites: eyelids, mouth, genitals
• slower resolution

Question 3

urticaria vs angioedema histology

Answer 3

urticaria: upper and middle dermis
angioedema: lower and subcutaneous tissue

Question 4

pathophysio of urticaria and angioedema

Answer 4

mast cell degranulation

• histamine = itch neuronal pathway
• vasodilation, increased blood flow, pruritus = wheals
• neuropeptides = wheal and flare response

Question 5

primary mediator of wheal and flare reaction

Answer 5

histamine

Question 6

acute vs chronic urticaria

Answer 6

acute <6 wks

chronic >6 wks

Question 7

t/f atopic individuals are at increased risk for acute urticaria, while non-atopic individuals are at risk for chronic urticaria

Answer 7

true

Question 8

t/f progressive acute urticaria should be periodically reevaluated

Answer 8

true

Question 9

most common cause of acute urticaria

Answer 9

transient viral infections

Question 10

t/f empiric elimination diets are always recommended in acute urticaria

Answer 10

false

Question 11

causes of acute urticaria

Answer 11

immunologic: ige and non-ige mediated

non-immunologic: radiocontrast, viral, opiates, nsaids

Question 12

t/f etiologic agents in chronic urticaria are usually identifiable, while agents in acute are more diverse

Answer 12

false, baliktad

Question 13

classification of urticaria subtypes

Answer 13

read

Question 14

diagnosis of cold contact urticaria

Answer 14

suspect: rapid onset local pruritus and erythema after exposure to cold stimulus

dx: challenge testing with ice cube for 10-15 mins
(+) = reaction when rewarming chilled skin

Question 15

manifestation of delayed pressure urticaria

Answer 15

• 4-6 hrs after pressure
• more angioedema
• perivascular mononuclear infiltrate
• sites of tight clothing

Question 16

dx for delayed pressure urticaria

Answer 16

challenge testing by pressure applied perpendicular to skin

Question 17

manifestation of solar urticaria

Answer 17

• 1-3 mins after sun exposure (pruritus –> edema)

- confined to sun exposed areas

Question 18

rare inborn error of metabolism confused with solar urticaria

Answer 18

eryhtropoietic protoporphyria

Question 19

dx of dermatographism

Answer 19

• can come with cholinergic or cold urticaria
• stroke skin with tongue depressor

cause: reflex vasoconstriction followed by pruritus, erythema, and linear wheal

Question 20

pathogenesis of cholinergic urticaria

Answer 20

• associated with exercise, hot showers, sweating
• mediated by cholinergic nerve fibers on muscle and sweat glands
• elevated histamine triggered by changes of body temp

Question 21

most common cause of chronic urticaria

Answer 21

idiopathic (but diagnosed by exclusion)

Question 22

erythema multiforme

Answer 22

• ringed/target lesions
• persistent sx
• no prominent pruritus

Question 23

urticarial vasculities

Answer 23

• palpable purpura/discoloration usually in lower extremities
• hives >24 hrs
• poor response to antihistamines

Question 24

possible pe results

Answer 24

• linear wheals = dermographism
• small wheals with erythema = cholinergic urticaria
• wheals in exposed areas = solar/cold
• wheals on lower extremities = urticarial vasculitis

Question 25

t/f acute and chronic urticaria always requires specific diagnostic tests

Answer 25

false, depends on history and pe

Question 26

routine diagnostic tests for acute and chronic urticaria

Answer 26

acute: none chronic: cbc, esr/crp, omission of drugs

Question 27

diagnostic tests for subtypes of urticaria

Answer 27

read

Question 28

principles of skin prick test

Answer 28

- site: volar surface of the forearm - agents: positive control histamine, negative control saline or extract diluent - immediate response is seen after 15-20 mins - diameter more/= 3x3 mm is positive

Question 29

t/f medications like antihistamine should be stopped one to several days prior to skin testing

Answer 29

true

Question 30

diagnostic test for chronic urticaria

Answer 30

autologous skin test | - serum from patient is intradermally injected into skin

Question 31

what is autoimmune urticaria

Answer 31

patients have anti-ige antibodies instead of anti-ige receptor antibodies (more severe)

Question 32

first line treatment for urticaria

Answer 32

antihistamines/h1 receptor antagonists - first gen for children - can give 2nd gen, best routinely

Question 33

indications for use of corticosteroids

Answer 33

- urticarial vasculitis - delayed pressure urticaria always use lowest effective dose!!

Question 34

+ and - of cyclosporine

Answer 34

+: inhibits basophil histamine release (mast cell degranulation) -: red swollen gums, abnormal hair growth

Question 35

other medications for urticaria

Answer 35

- phototherapy: reduces mast cells for dermographism and chronic idiopathic urticaria - omalizumab: chronic idiopathic, cholinergic, solar, cold - leukotriene receptor antagonist - h2 antagonists

Question 36

step 1 of approach to chronic urticaria

Answer 36

monotherapy with 2nd gen antihistamine, avoid triggers

Question 37

step 2 of approach to chronic urticaria

Answer 37

one or more of: - dose adjustment of 2nd gen ah - add another 2nd gen ah - add h2 antagonist - add leukotriene receptor antagonist - add 1st gen ah @ bedtime

Question 38

step 3 of approach to chronic urticaria

Answer 38

dose advancement of a potent antihistamine

Question 39

step 4 of approach to chronic urticaria

Answer 39

add alternative: - omalizumab or cyclosporine - immunosuppressants, biologics

Question 40

eaaci treatment algorithm for urticaria

Answer 40

- nsah -> 2 wks -> step up - nsah updosing up to 4x -> 1-4 wks -> step up - add leukotriene antagonist or change nsah -> 1-4 wks -> step up - add cyclosporine a, h2-ah, dapsone, omalizumab for exacerbations (step 3 and 4) use systemic steroid for 3-7 days