Drug reactions and the skin

Question 1

Drug reactions are immunologically/non-immunologically mediated?

Answer 1

Non-immunologically mediated

Question 2

Typical presentation

Answer 2

Patient who takes medication and develops a sudden symmetric skin eruption which usually resolves when the causative drug is withdrawn

Question 3

Who is most susceptible?

Answer 3

Extremes of age
Females
Patients with other associated diseases
Patients who have suffered from drug reactions before

Question 4

Common drugs which cause a skin reaction

Answer 4

NSAIDs

B-lactam compounds

Question 5

Exanthematous drug eruptions

Answer 5

Most common

Mild, self limiting

Question 6

Which type of hypersensitivity reaction is an exanthematous drug eruption?

Answer 6

Type IV

Question 7

Exanthematous drug eruptions - morphology

Answer 7

Flat
Erythematous macules/patches with patches 
Varies in size, usually widespread
Can become confluent 
Symmetrical distribution

Question 8

Exanthematous drug eruptions - symptoms

Answer 8

Itch, fever

Question 9

Exanthematous drug eruptions - mucosal involvement is usually present/absent ?

Answer 9

Absent

Question 10

Exanthematous drug eruptions - onset

Answer 10

4-21 days after taking first dose

Question 11

Exanthematous drug eruptions - causative drugs

Answer 11

penicillins 
sulphonamide antibiotics 
erythromycin
streptomycin
allopurinol
carbamazepine
NSAIDs
phenytonin
chloramphenicol

Question 12

Which type of hypersensitivity reaction is an urticarial drug eruption?

Answer 12

Type I

Question 13

Urticarial drug eruption - morphology

Answer 13

Raised

Itchy rash

Question 14

Urticarial drug eruption - onset

Answer 14

Up to 3 weeks after first exposure / minutes on re-challenge testing

Question 15

Urticarial drug eruption - causative drugs

Answer 15

b-lactam antibiotics
aspirin
opiates
NSAIDs
vancomycin
quinolones

Question 16

Pustular/bullous drug eruptions - AGEP

Answer 16

Acute Generalised Exanthematous Pustulosis

Rare, severe

Question 17

Pustular/bullous drug eruptions - AGEP morphology

Answer 17

Superficial pustules (small blisters filled with fluid)
Red rash
Usually starts on face/armpits/groin

Question 18

Pustular/bullous drug eruptions - AGEP causative drugs

Answer 18

CCB
Tetracyclines
Anti-malarials

Question 19

Pustular/bullous drug eruptions - Acne causative drugs

Answer 19

Glucocorticoids
Androgens
Lithium
Isoniaside
Phenytonin

Question 20

Pustular/bullous drug eruptions - Bullous pemphigoid morphology

Answer 20

Severe itch with large fluid filled blisters which can rupture to cause crusted erosions

Question 21

Pustular/bullous drug eruptions - bulls pemphigoid causative drugs

Answer 21

ACE inhibitors
Penicillin
Furosemide

Question 22

Fixed drug eruptions - morphology

Answer 22

Well demarcated oval plaques
May have central blisters
Red, painful

Question 23

Fixed drug eruptions - areas commonly affected

Answer 23

Mucosal surfaces such as lips, hands, genitalia

Question 24

Fixed drug eruptions - causative drugs

Answer 24

Paracetamol 
NSAIDs 
Tetracycline 
Doxycycline 
Carbamazepine

Question 25

Phototoxic drug eruptions

Answer 25

Lots of prescribed drugs absorb light which can make many patients light sensitive.
Can occur indoors through window glass (UVA)

Question 26

Phototoxic drug eruptions - acute presentation

Answer 26

Skin toxicity

Photodegradation

Question 27

Phototoxic drug eruptions - chronic presentation

Answer 27

Pigmentation

Photo ageing

Question 28

Phototoxic drug eruptions - chlorpromazine, amiodarone

Answer 28

Immediate prickling with delayed erythema

Question 29

Phototoxic drug eruptions - quinine, thiazides

Answer 29

Exaggerated sunburn

Question 30

Phototoxic drug eruptions - calcium channel antagonists

Answer 30

Telangiectasia

Question 31

Phototoxic drug eruptions - amiodarone

Answer 31

Increased skin fragility

Question 32

Management of a drug eruption

Answer 32

Ideally stop the drug and use an alternative
Topical steroids
Anti-histamines