Urticaria and Drug Rashes - Schwarzenberger

Question 1

Describe the pathophysiology of urticaria

Answer 1

An inflammatory skin reaction caused by the release of histamine/other cytokines

Question 2

Are all cases of urticaria allergen associated?

Answer 2

No, allergic or non-allergic

Question 3

Timeframe of urticaria? Why is this important?

Answer 3

Each individual urticaria wheal will last no longer than 24 hours; if a single wheal lasts longer, reconsider the dx

(but whole episode can last longer)

Question 4

What is angioedema in the context of urticaria? how long does it last?

Answer 4

swelling of the deeper dermis and subQ tissue; up to 72 hours

Question 5

Drugs that commonly cause acute urticaria?

Answer 5

B-lactam abx, NSAIDs, ASA, opiates, IV radiocontrast

Question 6

What cause of acute urticaria is seen in children frequently, but not in adults?

Answer 6

Food allergen induced

Question 7

Differentiation between acute urticaria vs. chronic urticaria (how long does each last?)

Answer 7

Acute–> less than 6 weeks Chronic–> more than 6 weeks

Question 8

Disease associated with chronic urticaria (I know it’s vague, she threw this out in class though)

Answer 8

Hashimoto’s Thyroiditis

Question 9

Common locations of angioedema?

Answer 9

Lips, periorbital areas, hands, and feet

Question 10

Why can ACE inhibitors cause angioedema?

Answer 10

Angiotensin converting enzyme normally breaks down Bradykinin

Question 11

Hereditary angioedema cause (Angelina Jolie syndrome)?

(Angiolina Joliedema)

Answer 11

C1 inhibitor deficiency

Question 12

Hoarseness in a patient in with angioedema. What are you worried about?

Answer 12

airway compromise

Question 13

What is dermatographism?

Answer 13

condition of mast cell degranulation upon pressure application

Question 14

What non immunologic things can cause urticaria?

Answer 14

Cold, heat, pressure, solar exposure, water

Question 15

Primary therapy in uritcaria?

Answer 15

2nd generation anti-histamines

Question 16

Why do you NOT use systemic glucocorticoids in urticaria?

Answer 16

risk of rebound urticaria

Question 17

What is the most common cause of acute urticaria (hint: it’s not drug related)?

Answer 17

Viral infection

Question 18

What do you assume as diagnosis when you see urticaria +24 hours (INDIVIDUAL lesions past 24 hours) ? What must you do at this point?

Answer 18

Assume urticarial vasculitis; biopsy the lesion

Question 19

Risk factors for developing a cutaneous Rx rash?

Answer 19

Increased age, female gender, concomitant viral infection (HIV/EBV)

Question 20

Most common drugs that cause cutaneous Rx induced rash (there’s 3)?

Answer 20

Abx, anticonvulsants, NSAIDs

Question 21

Misdiagnose a patient with a bacterial infection and give them an abx. They break out with acute urticaria. What do you assume the correct diagnosis to be?

Answer 21

EBV infection; this precipitated the cutaneous abx rash

Question 22

List the 5 types of cutaneous drug reactions discussed in the lecture? Frequency of 2 she mentioned?

Answer 22

• Morbilliform “maculopapular” rash - 90%
• Urticarial rash - 5%
• DRESS (Drug rash w/ eosinophilia and systemic symptoms
• Fixed Drug reaction
• Stevens-Johnson Syndrome/Toxic epidermal necrolysis

Question 23

Most common distribution of cutaneous Rx rash?

Answer 23

90% are morbilliform (maculopapular)

Question 24

Describe a mobilliform rash

Answer 24

Multiple small, pink, itchy papules on the trunk or pressure bearing areas (especially back/shoulders); spreads out over time to become confluent

Question 25

How long does a morbilliform Rx rash take to form? What type of reaction?

Answer 25

5-7 days; it's a Type IV cell mediated hypersensitivity

Question 26

Course of morbilliform Rx rash?

Answer 26

Almost all resolve spontaneously in 1-2 weeks

Question 27

Most common causes of MORBILLIFORM drug reactions?

Answer 27

PCNs, Cephalosporins, Sulfonamides, anticonvulsants

Question 28

How long does a urticarial Rx drug reaction take to form? what type of reaction?

Answer 28

minutes of exposure; it's a Type I (IgE mediated) hypersensitivity

Question 29

Most common causes of acute URTICARIAL Rx reactions?

Answer 29

PCNs, cephalosporins, ASA, latex (omar)

Question 30

What must have happened previously for an acute URTICARIAL rash to be possible?

Answer 30

Prior exposure and sensitization to that antigen

Question 31

What else is Drug rash with eosinophilia and systemic symptoms (DRESS) known as?

Answer 31

Drug hypersensitivity syndrome

Question 32

Describe the presentation seen in DRESS

Answer 32

Severe morbilliform reaction with eosinophilia and systemic illness

Question 33

Onset of DRESS?

Answer 33

2-6 weeks post exposure

Question 34

Systemic symptoms of DRESS?

Answer 34

Fever, joint pain, LAD

Question 35

Visceral involvement in DRESS?

Answer 35

multisystem, liver commonly affected

Question 36

Drugs commonly causing DRESS?

Answer 36

anticonvulsants (Carbamazepine most common), Allopurinol (also very common), sulfonamides, minocycline, erthyromycin

Question 37

Treatment of DRESS?

Answer 37

long term therapy with systemic corticosteroids

Question 38

Is DRESS fatal?

Answer 38

Yes, 10% due to severe hepatic failure

Question 39

Describe the lesion seen in a fixed drug eruption

Answer 39

A well circumscribed, red-brown plaque; may blister; reaction occurs in the exact same place if patient is re exposed

Question 40

How does a fixed drug eruption appear when it heals?

Answer 40

hyper-pigmented

Question 41

Most common areas for a fixed drug eruption

Answer 41

Genitals, lips, extremities

Question 42

Common causes of fixed drug eruption

Answer 42

sulfonamides, NSAIDs, poopoo powder (laxatives)

Question 43

What is Stevens-Johnson Syndrome/Toxic epidermal necrolysis?

Answer 43

Potentially life threatening spectrum of blistering skin disease

Question 44

Most common cause of SJS/TEN (think very generally)?

Answer 44

Drugs (almost all are drug related)

Question 45

Most common drugs causing SJS/TEN?

Answer 45

Abx, anticonvulsants, allopurinol, NSAIDs, Nevirapine, Abacavir, Acetaminophen (children)

Question 46

What do you need to make an official diagnosis of SJS/TEN (physical exam findings)?

Answer 46

Skin AND oral mucosal involvement

Question 47

Describe the presentation/onset of SJS/TEN

Answer 47

Onsets 1-2 months post exposure; begins influenza like (SORE THROAT, myalgias, fever); skin develops DUSKY TARGET LESIONS (buzz word); patients will present saying "THEIR SKIN HURTS"

Question 48

What does SJS/TEN look like on histologic examination?

Answer 48

A very clean split between the epidermis and dermis; not much inflammation at the separation site

Question 49

Tx for SJS/TEN?

Answer 49

STOP THE OFFENDING AGENT; supportive care in a burn unit with aggressive wound care; DO NOT give prophylactic abx

Question 50

Why do you NOT give corticosteroids to SJS/TEN patients?

Answer 50

Increases mortality; development of infection from immunosuppression

Question 51

What do patients with SJS/TEN die of, if they pass?

Answer 51

Sepsis