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Year 3 Semester 2 > Dermatology > Flashcards

Dermatology Flashcards

1
Q

Circinate balanitis is a manifestation of which disease?

A

Reactive arthritis

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2
Q

Keratoderma blenorrhagica is a manifestation of which disease?

A

Reactive arthritis

May resemble psoriasis. Commonly found on palms and soles

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5
Q

Which dermatological conditions are associated with reactive arthritis?

A

Balanitis circinata

Keratoma blenorrhagicum

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6
Q

List 4 causes of erythema nodosum

A
  1. Post-strep throat
  2. Sarcoidosis
  3. Tuberculosis
  4. Pregnancy
  5. IBD
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7
Q

Pyoderma gangrenosum is found most commonly in which disease?

A

IBD

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8
Q

List 4 distinctive features of Kawasaki disease

A
  1. C - conjunctivitis (no exudate)
  2. rash (polymorphous, originating on trunk)
  3. adenopathy (cervical lymphadenopathy)
  4. strawberry tongue (+ cracked and red lips)
  5. hands and feet (oedema and erythema)
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9
Q

What is the major complication of Kawasaki disease and when does it occur?

A

Coronary artery aneurysm

2-3 weeks after symptom onset

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10
Q

Koplik spots are found in which disease?

A

Measles

(prodromal stage, 1-2 days before the rash)

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11
Q

Explain the progression of the rash in measles

A

Begins on the face and behind the ears 2 weeks after exposure

Spreads to the trunk and extremities within 24-36 hours

Lasts 3-4 days

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12
Q

What is this sign and when is it present?

A

Rubella

Forchheimer sign

Petechiae on the soft palate and uvula during the prodromal period

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13
Q

A sandpaper-like textured rash is characteristic of which disease?

A

Scarlet fever

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14
Q

Where are Pastia’s lines are found?

Which disease are they characteristic of?

A

Scarlet fever

Groin, underarm, elbow creases

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15
Q

What causes hand, foot and mouth disease?

A

Coxsackie A

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16
Q

What is the pathophysiology of HSP?

A

Exposure to allergen/antigen e.g. infection, drugs → stimulation of IgA production → deposition of IgA immune complexes in vascular walls e.g. skin, GI tract, joints, kidneys → activation of complement → vascular inflammation and damage

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17
Q

What is the most common infection to precede HSP?

A

URTI caused by group A streptococcus

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18
Q
A

Roseola

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19
Q
A

Scarlet fever

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20
Q
A

Rubella

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21
Q
A

Measles

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22
Q
A

Erythema infectiosum

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23
Q

What is an enanthem?

A

Rash on mucous membranes

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24
Q

Identify two rashes in children which are characteristically cephalocaudal

A
  1. Measles
  2. Rubella (German measles)

(head to tail)

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25
Q

What are the characteristic features of a measles prodrome?

A

Three c’s

  1. Conjunctivitis
  2. Cough
  3. Coryza
    * This respiratory prodrome is characteristic and distinctive*
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26
Q

What is the treatment for Kawasaki disease?

A

IV immunoglobulin

High dose aspirin (antiplatelet effects)

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27
Q

Which age groups are at highest risk of meningococcal disease?

A

Children 6 months - 4 years

Teenagers 15 - 19 years

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28
Q

What is the pathophysiology of the rash in meningococcal disease?

A

Bacterial toxin –> disseminated vasculitis –> leakage of RBCs into tissue –> NON-BLANCHING rash (petechiae which progress to purpura)

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29
Q

What causes meningococcal disease?

A

Neisseria meningitidis

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30
Q

When does the rash in erythema infectiosum occur?

A

After the slapped cheeks

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31
Q

What causes roseola?

A

Herpes virus 6

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32
Q

A high temperature which resolves and is followed by a rash is characteristic of which disease?

A

Roseola

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33
Q

Oedematous eyelids and a bulging fontanelle is associated with which childhood illness/rash?

A

Roseola

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34
Q

Which childhood rash is also associated with tender and swollen retroauricular, occipital and posterior cervical lymph nodes

A

Rubella

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35
Q

What is the pathophysiology of scarlet fever?

A

Bacterial toxin-mediated

Group A streptococcus

Occurs in <10% of streptococcal tonsillopharyngitis

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36
Q

Where does the rash of scarlet fever start?

A

Below the ears, neck, chest, armpits and groin

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37
Q

Which medication is contraindicated in people with EBV?

A

Ampicillin

Leads to a morbilliform rash

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38
Q

What is the triad of congenital rubella syndrome?

A
  1. Cataracts
  2. Cochlear defect (bilateral sensorial hearing loss)
  3. Cardiac defect (patent dustus arteriosus, pulmonary artery stenosis)
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39
Q

What type of hypersensitivity reaction is allergic contact dermatitis?

A

IV

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40
Q

What causes impetigo?

A

Staphylococci or group A B-haemolytic streptococci

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41
Q

What causes erythrasma?

A

Corynebacterium minutissimum

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42
Q

Which rash is coral-red under Wood’s lamp?

A

Erythrasma

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43
Q

What is the treatment for recent-onset, localised tinea?

A

Terbinafine gel

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44
Q

What are two treatment options for cutaneous candidiasis?

A

“-azole” cream

Nystatin

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45
Q

What causes pityriasis versicolour?

A

Malassezia yeast

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46
Q

What is the treatment for pityriasis versicolour?

A

“-azole” cream

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47
Q

When is the typical onset of atopic dermatitis?

A

3 to 6 months of age

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48
Q

What are 3 treatment options for atopic dermatitis?

A
  1. Gentle skin care
  2. Topical corticosteroids
  3. Topical calcineurin inhibitors
  4. Antipruritics
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49
Q

What causes skin pigmentation in venous stasis eczema?

A

Haemosiderin deposition

RBCs breakdown and release haemosiderin

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50
Q
A

Dyshidrotic dermatitis

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51
Q

What are 3 dermatological complications of atopic dermatitis?

A
  1. Impetigo
  2. Eczema herpeticum
  3. Keratosis pilaris
  4. Ichthyosis vulgaris/palmar hyperlinearity
  5. Dennie-Morgan folds
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52
Q
A

Keratosis pilaris

Abnormal keratinisation of the lining of the upper portion of the hair follicle. Scale fills the follicle instead of exfoliating.

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53
Q
A

Ichthyosis vulgaris

Associated with atopic dermatitis

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54
Q
A

Dennie-Morgan folds

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55
Q
A

Eczema herpeticum

Disseminated herpes 1/2 infection w/ fever + rash + lymphadenopathy

Atopic people are susceptible

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56
Q

What is the pathological hallmark of dermatitis?

A

Spongiosis

Widening of the space between keratinocytes due to oedema

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57
Q

What is erythema multiforme?

A

Rare, acute hypersensitivity reaction most commonly triggered by herpes simplex infections

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58
Q
A

Keratosis pilaris

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59
Q

How is scabies treated?

A

Permethrin

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60
Q

What is the pathophysiology of serum sickness?

A

Type III hypersensitivity

Due to anti-toxin or anti-venom administration

Fever, urticarial rash, arthralgia, lymphadenopathy, gastrointestinal symptoms

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61
Q
A

Chicken pox

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62
Q

Name 2 less sedating antihistamines

A

Cetirizine (least sedating/Zyrtec)

Desloratadine

Fexofenadine

Loratadine

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63
Q

In which two instances is angioedema not IgE-mediated?

A

Direct mast-cell activation e.g. NSAIDs

Bradykinin-mediated e.g. ACEi-induced (impaired breakdown), hereditary angioedema (C1 esterase inhibitor deficiency)

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64
Q

What are indications for antiviral therapy for chicken pox?

A

Immunosuppression

Infection in people aged 13 and older

Acyclovir

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65
Q

What is the most common autoimmune blistering disease?

A

Bullous pemphigoid

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66
Q

When is the peak incidence of bullous pemphigoid?

A

>60 years

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67
Q

When is the peak incidence of pemphigus vulgaris?

A

40-60 years

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68
Q

When is the peak incidence of dermatitis herpetiformis?

A

15-40 years

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69
Q

Which autoimmune condition is strongly linked to dermatitis herpetiformis?

A

Coeliac disease

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70
Q

How is dermatitis herpetiformis treated?

A

Dapsone

Gluten-free diet

71
Q

How is pemphigus vulgaris treated?

A

High dose systemic steroids

Immunosuppression

72
Q

How is bullous pemphigoid treated?

A

High-dose topical steroids

Systemic glucocorticoids and immunosuppressants can be used if needed

73
Q

What is Nikolsy’s sign

A

Rubbing of the skin → upper epidermal layer slips away from lower layer → separation of the epidermis → blistering

74
Q

What are 3 conditions with a positive Nikolsky’s sign?

A
  1. Pemphigus vulgaris
  2. TEN
  3. SJS
  4. Staphylococcal scalded skin syndrome
  5. Scalding bullous impetigo
75
Q

What are two conditions with Tzanck cells in microscopic evaluation?

A
  1. Pemphigus vulgaris
  2. Herpes simplex 1
  3. Varicella zoster
  4. CMV
  5. SSSS
76
Q

Which condition is this?

Prodrome (urticarial lesions weeks to months beforehand)

Large, tense, subepidermal blisters

Intensely pruritic

A

Bullous pemphigoid

77
Q

Which condition is this?

Spontaneous onset of painful flaccid, intraepidermal blisters → lesions rupture and become confluent → erosions and crusts

Lesions present first on the oral mucosa then on body parts exposed to pressure e.g. intertriginous areas

Pruritis is absent

A

Pemphigoid vulgaris

78
Q

How does mucosal involvement differentiate SJS/TEN from SSSS?

A

Mucous membranes are spared in SSSS

Mucous membranes are almost always involved in SJS/TEN

79
Q

How are SJS/TEN differentiated?

A

The proportion of skin involvement

<10%: SJS

10-30%: overlap

>30%: TEN

80
Q

What is the strongest risk factor for SJS?

A

HIV infection (100x risk increase, 5% of patients)

81
Q

What are 4 drugs/drug classes that can cause SJS/TEN?

A
  1. Antibiotics (sulfonamides)
  2. Corticosteroids
  3. Antiretrovirals
  4. Antiepileptics
  5. Allopurinol
  6. Sulfasalazine
82
Q

When is the peak incidence of staphylococcal scalded skin syndrome (SSSS)?

A

Children < 6 years (98%)

83
Q

How does the quality of bullae vary between bullous pemphigoid and pemphigus vulgaris?

A

Bullous pemphigoid: tense, do not rupture easily

Pemphigus vulgaris: flaccid, rupture and crust

84
Q

Which condition is associated with autoimmune destruction of hemidesmosomes that attach basal keratinocytes to the underlying basement membrane

A

Bullous pemphigoid

85
Q

How do lesions from pemphigus vulgaris resolve?

A

Bullae rupture → crusting → hyperpigmentation without scarring

86
Q
A

Discoid lupus erythematosus

87
Q

What is the risk of progression from discoid lupus erythematosus to SLE?

88
Q

How do lesions from discoid lupus erythematosus heal?

A

Scar tissue with central atrophy

89
Q
A

Subacute cutaneous lupus erythematosus

Photosensitive annular plaques

90
Q

Which antibodies are associated with discoid lupus erythematosus?

A

None (often ANA and anti-Ro negative)

91
Q

Which antibodies are associated with subacute cutaneous lupus erythematosus?

A

Anti-Ro antibodies

92
Q

What is the pathophysiology of pemphigus vulgaris?

A

IgG antibodies against desmoglein 1 and 3 (mediate keratinocyte adherence)

93
Q

Which of the autoimmune blistering conditions typically first presents with mucosal lesions?

A

Pemphigus vulgaris

  • Lesions begin on the mucosa and spread to intertriginous areas*
  • Bullous pemphigoid and dermatitis herpetiformis rarely have mucosal involvement*
94
Q

Which of the autoimmune blistering conditions present with pruritis?

  • Bullous pemphigoid*
  • Pemphigoid vulgaris*
  • Dermatitis herpetiformis*
A

Bullous pemphigoid - intensely pruritic

Pemphigoid vulgaris - pruritis absent

Dermatitis herpetiformis - intensely pruritic

95
Q

Where is the most common place for scabies lesions to be seen?

A

Interdigital web spaces

96
Q

Which layer of the skin is affected by urticaria?

A

Dermis

Normal epidermis (no spongiosis or hyperplasia)

97
Q

Which layer of the skin is affected by angioedema?

A

Subcutaneous and submucosal surfaces - beneath the dermis

98
Q

How are the areas affected by angioedema and urticaria different?

A

Angioedema - skin and mucosa, including eyelids and lips

Urticaria - skin only

99
Q

How is pain, tenderness and pruritis different in angioedema and urticaria?

A

Urticaria - itch, no pain or tenderness

Angioedema - pain and tenderness, no itch

100
Q

What causes hereditary angioedema?

A

Congenital C1 esterase inhibitor deficiency

Leads to a buildup of bradykinin

101
Q

Target lesions are characteristic of which disease?

A

Erythema multiform

  1. Centre: dusky or dark red with blister or crust
  2. Middle: pale pink, raised due to oedema
  3. Outermost: bright red
102
Q

List 2 diseases which exhibit the Koebner phenomenon

A
  1. Psoriasis
  2. Lichen planus
103
Q

What is Auspitz sign and when is it positive?

A

Removal of scale → small bleeding points

Psoriasis

104
Q

Which four phenomenon contribute to the pathogenesis of acne?

A
  1. Hyperplasia of the sebaceous glands
  2. Hyperkeratinisation
  3. Propionibacterium acnes proliferation
  4. Inflammation
105
Q

Is pemphigus vulgaris subrabasal or subepidermal?

A

Suprabasal

106
Q

Is bullous pemphigoid suprabasal or subepidermal?

A

Subepidermal

107
Q

What is the gold standard for diagnosis of an autoimmune blistering condition?

A

Direct immunofluorescence

Allows for the detection of antibody or complement deposition within the skin

108
Q

What are 3 potential exacerbating factors for pemphigus vulgaris?

A
  1. Drugs (ACEi, phenobarbital, penicillin)
  2. Viruses
  3. UV
  4. Diet (onion, garlic, leaks)
109
Q

What is the pathophysiology of pemphigus vulgaris?

A

Antibodies against desmoglein 3 and 1

Desmosomes cause keratinocyte adherence in the stratum basale

110
Q

What is the pathophysiology of bullous pemphigoid?

A

Antibodies against the bullous pemphigoid antigen in the basement membrane

Destruction of hemidesmosome-associated proteins

Hemidesmosomes attach keratinocytes to the ECM

111
Q

What is the pathophysiology of dermatitis herpetiformis?

A

Cross reactivity of IgA anti-tissue transglutaminase with epidermal tissue-transglutaminase in the basement membrane

112
Q

What is DRESS syndrome?

A

Drug Reaction with Eosinophilia and Systemic Symptoms

113
Q

Which drug class most commonly causes DRESS?

A

Antiepileptics

Also xanthine oxidase inhibtiors and sulfonamides

114
Q

What is the mechanism of acitretin (neotigason) in treating psoriasis?

A

Reverses epidermal proliferation and increased keratinisation seen in hyperkeratotic disorders

115
Q

What is acantholysis?

A

The loss of intercellular connections, such as desmosomes, resulting in loss of cohesion between keratinocytes

116
Q

What types of cells are seen on a Tzanck smear?

A

Giant multinucleated cell secondary to acantholysis

117
Q

What does direct immunofluorescence detect?

A

Antibody deposition

118
Q

What is the pathophysiology of SSSS?

A

Staphylococcus epidermolytic toxins A and B bind to desmoglein 1, impairing keratinocyte adherence

→ acantholysis + Tzanck cells

119
Q

What are histological features of urticaria?

A
  1. Superficial dermal oedema
  2. Dilated blood vessels with perivascular inflammatory cells
  3. Normal epidermis
120
Q

What are the histological features of eczema?

A
  1. Spongiosus
  2. Superficial perivascular lymphocytic infiltrate
121
Q

What is the pathophysiology of psoriasis?

A

Increased keratinocyte proliferation

→ acanthosis (thickening of the stratum spinosum)

→ parakeratosis (retention of nucleated keratinocytes in the stratum corneum)

122
Q
123
Q
A

Pemphigus vulgaris

Deposition of immunoglobulin and complement along keratinocyte membranes gives a “fish-net” appearance

124
Q
A

Bullous pemphigoid

Deposition of linear IgG and C3 along the dermoepidermal junction

Bullous pemphigoid antigen causes subepidermal separation

125
Q

Where is pain from the gallbladder referred to?

A

Right shoulder

126
Q

What is poikiloderma?

A

Skin with areas of hypopigmentation, hyperpigmentation, telangiectasias and atrophy

Commonly in sun-exposed areas

127
Q

What is the shawl sign?

A

Poikiloderma found on the upper back, characteristic of dermatomyositis

128
Q

What is the V sign?

A

Poikiloderma in the neck and upper chest, characteristic of dermatomyositis

Proposed mechanism: complement-induced microvascular damage

129
Q

What are 2 diseases associated with calcinosis cutis?

A

Systemic sclerosis (particularly limited)

Dermatomyositis

SLE

130
Q

A heliotrope rash and Gottron’s papules are characteristic of which disease?

A

Dermatomyositis

131
Q

What are periungual telangiectasias suggestive of?

A

Autoimmune connective tissue diseases

SLE, scleroderma, dermatomyositis

132
Q

What is onycholysis?

A

Separation of the nail plate from the nail bed

May be a feature of psoriasis

133
Q

What are 3 psoriatic nail changes?

A
  1. Pitting of the nail bed
  2. Subungual hyperkeratosis
  3. Onycholysis (nail lifting)
  4. Oil drops and salmon patches
  5. Splinter haemorrhages
134
Q

What is the proposed mechanism of dactylitis in spondyloarthropathies?

A

Enthesitis → inflammatory cytokines → synovitis and swelling of surrounding structures

135
Q

Where are rheumatoid nodules most commonly found?

A

Extensor surfaces

136
Q

What is the pathophysiology of rheumatoid nodules?

A

Repeated trauma → local vascular damage → endothelial injury + IgM RF immune complex formation → complement → inflammation → granuloma formation

137
Q

How are localised impetigo lesions treated in non-remote community settings?

A

Mupirocin topically

138
Q

How are multiple/recurrent impetigo lesions treated in non-remote community settings?

A

Di/flucloxacillin orally

139
Q

How is impetigo in remote community settings and Northern Australia treated?

A

Benzathine penicillin IM as a single dose

OR

Trimethoprim + sulfamethoxazole

140
Q

What are three ways of diagnosing prior GAS infection?

A
  1. Positive throat culture for group A beta-haemolytic streptococci
  2. Positive rapid streptococcal antigen
  3. Elevated or rising antistreptococcal antibody titre - either antistreptolysin O (ASO) or anti-deoxyribonuclease B (ADB)
141
Q

Which immune cell predominates in the infiltrate of bullous pemphigoid?

A

Eosinophils

142
Q

What is eczema herpeticum?

A

Disseminated herpes 1/2 infection w/ fever + rash + lymphadenopathy

143
Q

What is crusted/Norwegian scabies?

A

Highly contagious super infestation with Sarcoptes scabiei var hominis

144
Q

What are 5 risk factors for crusted scabies? (Sarcoptes scabiei var hominis )

A
  1. Increased age
  2. Dementia
  3. Down syndrome
  4. HIV
  5. SLE
  6. Long-term corticosteroid or immunosuppressant use
  7. Institutional accommodation e.g. prisons, nursing homes
  8. Lymphoma
145
Q

What causes pityriasis rosea?

A

Herpes 6 and 7

146
Q

What is miliaria?

A

Sweat rash

Blockage and/or inflammation of eccrine sweat ducts

Frequently seen in hot, humid or tropical climates

147
Q

What is pediculosis corporis?

A

Body lice

Plural lice

148
Q

What is the medical term for lice?

A

Pediculosis

149
Q

What causes pityriasis versicolour?

A

Malassezia

150
Q

What is papular purpuric gloves and socks syndrome?

A

Rash most strongly associated with parvovirus B19

151
Q

Which childhood exanthems may present with a strawberry tongue?

A

Scarlet fever

Kawasaki

152
Q

What is the major complication of measles?

A

Subacute sclerosing panencephalitis

Dementia, myoclonus and epilepsy leading to coma and death

7-10 years later

153
Q

Which paediatric exanthem is treated with vitamin A and why?

A

Prevention of severe exfoliative dermatitis in malnourished children with measles

154
Q

Where does the rash of roseola originate?

155
Q

Which paediatric exanthem is more pronounced after exposure to sunlight or heat?

A

Erythema infectiosum

156
Q

Which paediatric exanthems begins with a prodrome of acute tonsillitis?

A

Scarlet fever

157
Q

What is the pathophysiology of parvovirus B19?

A

Binds to erythroid progenitor cells → cellular invasion → viral DNA enters the nucleus of erythroid cells → viral DNA replication → cytotoxicity → clinical manifestations + transient cessation of erythropoiesis

158
Q

What are the features of parvovirus B19-associated arthritis?

A

Symmetrical, non-destructive

Small joints - fingers, hand, knee, ankle (similar to RA)

Self-resolving in most

159
Q

Which patients develop a transient aplastic crisis with parvovirus B19 infection?

A

Patients with haematological conditions

Haemolytic: sickle cell disease, hereditary spherocytosis

Decreased production: iron deficiency anaemia, thalassemia

160
Q

Which paediatric exanthem is non-infectious?

A

Kawasaki disease

Immune-mediated

161
Q

What infection commonly proceeds guttate psoriasis?

A

Streptococcal pharyngitis

162
Q

How is pediculosis corporis treated?

A

Washing/ironing clothes

Lice live and lay their eggs in clothes rather than on the body

163
Q

What causes pruritis in scabies?

A

Excretions from mites and decomposing bodies → antigens → type IV hypersensitivity reaction → pruritus and excoriation

164
Q

Which childhood exanthems may present with arthritis?

A

Parvovirus

Rubella

165
Q

How can rubella and measles be differentiated?

166
Q

What is the difference between a skin prick and skin patching?

A

Prick = IgE-mediated responses

Patch = allergic contact dermatitis

167
Q

When is in vitro allergy testing preferred over skin pricks?

A
  1. When the patient is on antihistamines
  2. If skin testing carries a high risk of anaphylaxis
  3. Comorbid dermatological conditions preclude testing e.g. severe atopic dermatitis
168
Q

How are allergen immunoassays performed?

A
  1. Serum is incubated with the allergen in question
  2. Bound IgE is detected with an anti-IgE antibody
169
Q

What causes bullous impetigo?

A

Staph - exfoliative toxins targeting desmogelin

170
Q

How is scabies diagnosed?

A

Dermatoscopy

Skin biopsy

171
Q

Which organism causes scabies?

A

Sarcoptes scabiei

Year 3 Semester 2 (7 decks)

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