1: Drug Reactions

Question 1

Define urticaria

Answer 1

Leakage of fluid from capillaries and small venules

Question 2

Define angioedema

Answer 2

Localised swelling of dermis, subcutaneous and submucosal tissue due to leakage of fluid in the interstitium

Question 3

What are 5 causes of urticaria

Answer 3

1. Food
2. Bites
3. Infection
4. Medications
5. Contact - latex
6. Hereditary

Question 4

Where is swelling in urticaria

Answer 4

in the superficial dermis - which raises the epidermis

Question 5

How will urticaria present clinically

Answer 5

wheal

Question 6

What is angioedema

Answer 6

swelling of the dermis and deeper subcutaneous tissue

Question 7

How will angioedema present

Answer 7

swelling of the tongue and lips

Question 8

What is anaphylaxis

Answer 8

oedema of the face and larynx. Associated with bronchospasm and hypotension

Question 9

What is the typical progression of anaphylaxis

Answer 9

Starts with urticaria, may progress to angioedema and then anaphylaxis

Question 10

What is the main mediator of urticaria and angioedema

Answer 10

Histamine release from mast cells

Question 11

How is urticaria managed

Answer 11

Anti-histamine

Question 12

How is angioedema managed

Answer 12

Corticosteroids

Question 13

What is a drug eruption

Answer 13

adverse cutaneous reaction to medication

Question 14

What is a simple drug eruption

Answer 14

cutaneous reaction resolves once drug is ceased

Question 15

What are two types of possible drug eruption

Answer 15

• Urticarial

- Exanthematous

Question 16

What is a type I hypersensitivity reaction

Answer 16

IgE mediated

Question 17

Give an example of a type I hypersensitivity reaction

Answer 17

Urticaria, Angioedema, Anaphylaxis

Question 18

What is a type II hypersensitivity reaction

Answer 18

Cytotoxic reaction

Question 19

What causes type II hypersensitivity reactions

Answer 19

IgM and IgG antibodies

Question 20

What is a Type III hypersensitivity reaction

Answer 20

Immune-Complex mediated hypersensitivity reaction

Question 21

What is a type IV hypersensitivity reaction

Answer 21

Delayed Hypersensitivity reaction

Question 22

What mediates a type IV hypersensitivity reaction

Answer 22

T lymphocytes

Question 23

What is erythema multiforme

Answer 23

Hypersensitivity reaction commonly triggered by infection

Question 24

What is a typical distinguishing feature of erythema multiforme

Answer 24

there is NO (repeat NO) mucosal involvement

Question 25

Explain the relationship between Steven Johnson syndrome and Erythema multiforme

Answer 25

Use to think steven Johnson was a severe form of erythema multiforme - now know that is different and they are separate entities.

Question 26

What age group does erythema multiforme occur in

Answer 26

20-40 years

Question 27

What is the most common cause of erythema multiforme

Answer 27

Infection

Question 28

What infection causes 50% of erythema multiforme

Answer 28

HSV

Question 29

What medications may cause erythema multiforme

Answer 29

- Phenytoin - Barbituates - Salphonamides - NSAIDs - Penicillin

Question 30

What lesions are pathognomic of erythema multiforme

Answer 30

Target Lesions

Question 31

Explain the presentation of erythema multiforme

Answer 31

Acute onset erythematous macules, progress to papules and after a few days target lesions will appear Target lesions = dark inner circle, pale surrounding circle and dark erythematous ring

Question 32

Which areas does erythema multiforme tend to affect first

Answer 32

Hands, Feet, Back and then the trunk

Question 33

How is erythema multiforme managed

Answer 33

Stop medication | Treat infection

Question 34

What is Steven Johnson Syndrome

Answer 34

Immune-mediated skin reaction with blistering of the skin and significant epidermal detachment

Question 35

What is the most common cause of Steven Johnson Syndrome

Answer 35

Medications

Question 36

What percentage of SJS is caused by medications

Answer 36

80%

Question 37

What medications can cause SJS (5)

Answer 37

``` Corticosteroids ART Anti-epileptics Allopurinol Sulphonamides Sulfasalazine ```

Question 38

What infections may cause SJS (3)

Answer 38

- Mycoplasma - CMV - Herpes

Question 39

In which individuals is there a higher risk of SJS

Answer 39

HIV

Question 40

How long after medication does prodrome of SJS usually start

Answer 40

1-3W

Question 41

What is the prodrome phase of SJS

Answer 41

- High fever >39 - Malaise - Myalgia

Question 42

How does the cutaneous aspect of SJS present

Answer 42

1. Painful erythematous purpuric macules 2. Formation of bullae 3. Full-Thickness epidermal necrosis and sloughing

Question 43

What sign is positive in SJS

Answer 43

Nikolosky's sign

Question 44

What is Nikolosky's sign

Answer 44

On touching epidermis it will slough off

Question 45

What is a key differentiating feature between erythema multiforme and SJS

Answer 45

- Erythema multiforme: NO mucosal involvement | - SJS: Mucosal involvement

Question 46

How will mucosal involvement in SJS present

Answer 46

- Stomatitis, Chelitis, Oral Ulcers, Odynophagia - Urethritis - Conjunctivitis

Question 47

What type of hypersensitivity reaction is SJS

Answer 47

Type 4

Question 48

What mediates type 4 hypersensitivity reactions

Answer 48

Cytotoxic T cells

Question 49

Explain pathophysiology of SJS

Answer 49

- Cytotoxic T cells raise an immune response to epidermal cells causing necrosis and sloughing - Sloughing of the epidermis can lead to dehydration. Also impedes barrier function resulting in bacterial superinfection

Question 50

What is on the same spectrum as SJS

Answer 50

TEN

Question 51

How do SJS and TEN differ

Answer 51

Depending on % body area affected

Question 52

What percentage of surface area affected indicates SJS

Answer 52

<10%

Question 53

What percentage of surface area affected indicates SJS and TEN

Answer 53

10-30%

Question 54

What percentage of surface area affected indicates TEN

Answer 54

>30%

Question 55

Explain management for SJS

Answer 55

1. Remove cause 2. Antibiotics for infection 3. Cleanse wounds, irrigate with chlorhexidine, greasy emollient, apply non-adherent dressing 4. IV fluids 5. Daily ophthalmology and oral review

Question 56

What prognostic score is used for SJS

Answer 56

SCORTEN | - calculate in first 24h

Question 57

What is ophthalmological complication of SJS

Answer 57

keratoconjunctivitis sicca

Question 58

What is toxic epidermal necrolysis

Answer 58

Life-threatening skin disorder caused by immune-mediated reaction to medications

Question 59

What most commonly causes TEN

Answer 59

Medications

Question 60

Aside from drug reactions that cause 80% of TENS, what is the second most common cause

Answer 60

HSV

Question 61

List common drugs that can cause TENS (PPCANS)

Answer 61

``` Penicillin Phenytoin Carbamezapine Allopurinol NSAIDs Sulphonamide ```

Question 62

What is a risk factor for TENS

Answer 62

HIV

Question 63

How long after drug ingestion does pro-drome of TENS present

Answer 63

1-3W

Question 64

What are the prodromal features of TENS

Answer 64

Fever >39 Malaise Lymphadenopathy Myalgia

Question 65

Explain the cutaneous manifestation of TEN

Answer 65

Painful-erythematous macules/papules. Then blisters. Will separation of epidermis

Question 66

Explain the mucosal manifestation of TEN

Answer 66

Oral: pharyngitis, chelitis Conjunctivitis Urethritis

Question 67

What is another feature of TEN

Answer 67

Shock

Question 68

What type of hypersensitivity reaction is TEN

Answer 68

type IV

Question 69

What % of body area is affected in TEN

Answer 69

>30%

Question 70

What % mortality of TEN

Answer 70

30