Pathology

Question 1

Name an anaphylactic (Type I) cutaneous drug eruption

Answer 1

Urticaria

Question 2

Name 2 cytotoxic (Type II) cutaneous drug eruptions

Answer 2

Pemphigus

Pemphigoid

Question 3

Name an immune-complex mediated (Type III) cutaneous drug eruption

Answer 3

Purpura/rash

Question 4

Name a T cell mediated delayed (Type IV) cutaneous drug eruption

Answer 4

Erythema/rash

Question 5

Are immunologically-mediated drug reactions dose-dependent?

Answer 5

No

Question 6

Give examples of dose dependent cutaneous reactions

Answer 6

Those that are “non-allergic”

e.g. eczema, psoriasis, pigmentation, cheilitis

Question 7

How do majority of cutaneous drug eruptions present?

Answer 7

Exanthematous (maculopapular) 75-95%

Question 8

What are other morphologies of cutaneous drug eruptions presentation?

Answer 8

Urticarial (5-10%)
Pustular/bullous
Pigmentation
Itch/pain
Photosensitivity

Question 9

When do we consider drug eruptions?

Answer 9

Patient on meds
Develops sudden skin signs
Symmetric appearance

Question 10

What affects the clearance of the reaction after drug withdrawal?

Answer 10

Half life of drug
Accumulation of drug in cells
Cross reaction with other substances

Question 11

What age group is most affected?

Answer 11

Young adults

Question 12

Which sex is most affected?

Answer 12

Females

Question 13

Name 3 drugs associated with exanthematous drug eruptions

Answer 13

Penicillins
Sulphonamide antibiotics
Erythromycin
(+6)

Question 14

Which drugs can cause an acne eruption?

Answer 14

Glucocorticoids
Therapeutic androgens
Lithium
Isoniazid
Phenytoin

Question 15

Which drugs can cause acute generalised exanthematous pustulosis?

Answer 15

• this is rare
  Antibiotics
  CCBs
  Antimalarials

Question 16

Which drugs can cause bullous pemphigoid?

Answer 16

ACE inhibitors
Penicillin
Furosemide

Question 17

What are fixed drug eruptions?

Answer 17

Present as well demarcated round plaques
Red and painful
Affects hands, genitalia, lips

Question 18

Which drugs can cause fixed drug eruptions?

Answer 18

Tetra/doxycycline
Paracetamol
NSAIDs
Carbamazepine

Question 19

Give 2 examples of severe cutaneous drug eruptions

Answer 19

Steven Johnson’s Syndrome
Toxic Epidermal Necrolysis
Drug rxn with eosinophilia and systemic symptoms (DRESS)
Acute generalised exanthematous pustulosis (AGEP)

Question 20

Give 3 examples of ACUTE phototoxic drug reactions

Answer 20

Skin toxicity
Systemic toxicity
Photodegradation

Question 21

Give 3 examples of CHRONIC phototoxic drug reactions

Answer 21

Pigmentation
Photoageing
Photocarcinogenesis

Question 22

What are phototoxic cutaneous drug reactions?

Answer 22

Non-immunological

Happens in anybody with enough photo-reactive drug+wavelength of light

Question 23

Which wavelengths of light are usually implicated in phototoxic cutaneous drug reactions?

Answer 23

UVA

Visible light

Question 24

Which 2 drugs can cause Immediate prickling with delayed erythema and pigmentation?

Answer 24

Chlorpromazine

Amiodarone

Question 25

Which 2 drugs can cause exaggerated sunburn?

Answer 25

Thiazides | Quinine

Question 26

Which drug can cause exposed telangectasia?

Answer 26

Calcium channel blockers

Question 27

Which 3 drugs can cause increased skin fragility?

Answer 27

Naproxen Amiodarone Tetracycline

Question 28

Which 4 investigations can be used to determine the cause of a cutaneous drug eruption?

Answer 28

Phototesting Biopsy Patch/photopatch tests Skin prick with specific drugs

Question 29

What is the most common porphyria?

Answer 29

Porphyria cutanea tarda (PCT)

Question 30

Which enzyme is faulty in people with porphyria cutanea tarda?

Answer 30

Uroporphyrinogen decarboxylase

Question 31

What is the typical presentation of PCT?

Answer 31

Blistering Skin fragility Hypertrichosis Morphoea

Question 32

How do you investigate for PCT?

Answer 32

Woods lamp

Question 33

Which enzyme is faulty in people with erythropoietic protoporphyria (EPP)?

Answer 33

Ferrochelatase

Question 34

Which porphyrin accumulates people with erythropoietic protoporphyria?

Answer 34

Protoporphyrin IX

Question 35

Describe the presentation of EPP

Answer 35

Swelling | Burning/itching

Question 36

What are the investigations for EPP?

Answer 36

Quantitative RBC porphyrins Fluorocytes Transaminases

Question 37

What sort of radiation do people with EPP need protection against?

Answer 37

Visible light

Question 38

How does acute intermittent porphyria present?

Answer 38

GI upset: - nausea, vomitting - constipation

Question 39

What is hyperkeratosis?

Answer 39

Increased thickness of keratin layer

Question 40

What is parakeratosis?

Answer 40

Persistence of nuclei in the keratin

Question 41

What is acanthosis?

Answer 41

Increased thickness of epidermis

Question 42

What is papillomatosis?

Answer 42

Irregular epithelial thickening

Question 43

What is spongiosis?

Answer 43

Oedema between keratinocytes

Question 44

Give 4 features of atopic eczema

Answer 44

Pruritus General erythema and scaling FLEXURAL distribution Other atopic diseases - asthma, etc

Question 45

List 3 features of chronic atopic eczema

Answer 45

Lichenification Excoriation Secondary infection (usu S. aureus)

Question 46

Describe the presentation of eczema herpeticum

Answer 46

Monomorphic punched out lesions | Very painful

Question 47

Describe the features of acne vulgaris

Answer 47

Open and closed comedones Pustules/papules Onset at puberty Affects regions with sebaceous glands

Question 48

Describe the features of rosacea

Answer 48

``` Recurrent facial flushing Visible blood vessels NO comedones Pustules seen Thickening of the skin (rhinophyma on nose) ```

Question 49

Name 4 factors that trigger rosacea

Answer 49

- sunlight - alcohol - spicy food - stress

Question 50

Name 3 immunobullous diseases

Answer 50

Pemphigus Bullous pemphigoid Dermatitis herpetiformis

Question 51

Describe the general features of pemphigus

Answer 51

Affects middle-ages Desmosomes between keratinocytes lost Responds to steroids Majority - pemphigus vulgaris

Question 52

What is desmoglein 3?

Answer 52

"DesmoGLUEin" Maintains desmosomal attachments So keeps keratinocytes together

Question 53

Give 5 features of pemphigus vulgaris

Answer 53

``` Autoimmune May affect mucosa IgG antibodies attack desmoglein 3 Immune complex forms on cell surface Leads to ACANTHOLYSIS ```

Question 54

What is acantholysis?

Answer 54

Lysis of intercellular adhesion sites | - common to all forms of pemphigus

Question 55

What is the more common presentation of pemphigus vulgaris?

Answer 55

Erosions | - the vesicles burst very easily

Question 56

How is pemphigus vulgaris diagnosed?

Answer 56

Biopsy of fresh blisters

Question 57

Give 5 features of bullous pemphigoid

Answer 57

``` Subepidermal blister Tense blisters NO acantholysis IgG attack hemidesmosomes between basal cells and basement membrane Old lesions resemble pemphigus vulgaris ```

Question 58

How is bullous pemphigoid diagnosed?

Answer 58

Biopsy of EARLY LESIONS

Question 59

What is the immunofluorescent pattern of IgG in the immunobullous diseases

Answer 59

Pemphigus vulgaris: Intraepidermal | Bullous pemphigus: along the basement membrane

Question 60

Give features of dermatitis herpetiformis

Answer 60

Autoimmune - mediated by IgA INTENSE itch Associated with coeliac disease and HLA-DQ2 haplotype

Question 61

What is the hallmark feature of dermatitis herpetiformis?

Answer 61

Papillary dermal microabscesses

Question 62

What does IgA target?

Answer 62

Gliadin in gluten | - but crossreact with connective tissue proteins

Question 63

On mucosal surfaces, how does lichen planus present?

Answer 63

Reticular white lines

Question 64

On skin, how does lichen planus present? [6Ps]

Answer 64

Purple Pruritic Polygonal Planar Papules and Plaques

Question 65

What is the most common viral cause of erythema multiforme?

Answer 65

Herpes Simplex Virus

Question 66

What causes molluscum contagiosum

Answer 66

Poxvirus