Cutaneous Drug Eruptions

Question 1

A type 3 allergic reaction is mediated by what? and Give a dermatological example of this type.

Answer 1

immune complex-mediated

purpura/rash

Question 2

A dermatology example of a type 2 allergic reaction.

Answer 2

pemphigus & pemphigoid

type 2 - cytotoxic

Question 3

Type 4 allergic reaction example.

Answer 3

erythema/rash

Question 4

Are immunologically-mediated reactions dose dependent?

Answer 4

allergic reactions are not dose-dependent

Question 5

A non-immunological reaction resulting in atrophy. Cause?

Answer 5

topical corticosteroids

Question 6

Which cancer treatment can result in non-allergic skin erosion?

Answer 6

5-Fluorouracil

Question 7

morbilliform?

Answer 7

measles-like morphology

Question 8

A patient taking new medication who suddenly develops a symmetrical skin eruption will most likely resolve when…? What needs to be considered?

Answer 8

Usually resolves when the drug is withdrawn.
Half-life of drug
Ability of drug to be retained/accumulate in tissue

Question 9

3 things to consider when a patient is on multiple drugs and has skin eruption?

Answer 9

1. Drug that is known to be most likely to cause an eruption
2. Time interval between exposure and development of skin reaction
3. History of previous exposure to the same drugs

Question 10

Describe a penicillin drug eruption.

Answer 10

Type 4 (delayed) hypersensitivity reaction
Usually mild & self-limiting
Widespread symmetrically distributed rash
Pruritus common
Mild fever common
Onset is 4-21 days post-1st dose
penicillin-induced exanthematous purport will BLANCHE

Question 11

Name other drugs with similar drug eruption as penicillin.

Answer 11

Sulphonamides
Erythromycin
allopurinol 
anti-epileptics
NSAIDs

Question 12

Describe urticarial drug reactions.

Answer 12

Type 1 reaction after re-challenge with drug or direct release of inflammatory mediators from mast cells on first exposure

Question 13

Nettle-rash hives which blanche may be associated with?

Answer 13

angioedema or anaphylaxis

draw a circle around it and it will have moved when you return to it, should be gone within the day

Question 14

What wouldn’t you expect to see if lithium was the cause of an acneiform drug eruption?

Answer 14

blackheads

lithium used in bipolar disease

Question 15

What is AGEP and which drugs cause it?

Answer 15

Acute generalised exanthematous pustulosis - a rare eruption caused by antibiotics, CCBs, and anti-malarial

Question 16

An autoimmune blistering disease with hemorrhagic blisters due to drugs such as ACE inhibitors and penicillin?

Answer 16

Drug-induced bullies pemphigoid

Question 17

Female patient has repeated red, painful, well-demarcated round/oval plaques occurring at same site one month apart…same spots on hands with urticaria?

Answer 17

fixed drug eruption - could be caused by paracetamol, NSAIDs, doxycycline

Occurs at same site every time - patient reacting to paracetamol taken for period pain

Question 18

List 4 severe cutaneous drug reactions.

Answer 18

SJS - Stevens-Johnson syndrome
TEN - Toxic epidermal necrolysis
DRESS - drug reaction with eosinophilia & systemic symptoms
AGEP - acute generalised exanthematous pustulosis

Question 19

Which type of light usually causes phototoxic cutaneous reactions?

Answer 19

UVA/visible light e.g. through a glass window

Question 20

Quinine, thiazides & demeclocycline would cause which pattern of skin phototoxicity?

Answer 20

exaggerated sunburn

Question 21

CCBs cause which pattern of skin phototoxicity?

Answer 21

exposed telangiectasia

Question 22

amiodarone and tetracycline naproxen cause which pattern of skin phototoxicity?

Answer 22

increased skin fragility