Dermatology Flashcards

1
Q

what are the diagnostic criteria for lupus?

A

Mucocutaneous:

  • acute - photodistributed/sun-exposed rash
  • chronic - alopecia
  • Oral ulcers
  • Alopecia
Synovitis
serositis  (pleuritis, pericarditis) 
Renal disease 
Neurological disorder 
Haemolytic anaemia, thrombocytopenia, leukopenia
Immunological: 
ANA
anti-dsDNA, anti-Sm, antiphospholipid
Low complement 
Direct coombs test
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2
Q

What are the findings in cutaneous (discoid) lupus erythematosus?

A

discoid lupus erythematous

SCLE

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3
Q

What are the cutaneous findings in systemic lupus erythematosus?

A
Alopecia 
Photodistributed rash 
Cutaneous vasculitis (manifesting as purpura) 
Chilblains 
Livedo reticularis 
 Subacute cutaneous lupus
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4
Q

In a newborn suspected of lupus, what test do you order? what are you testing for?

A

ECG - risk of heart block

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5
Q

A _ is indicated as a test in SLE for renal function

A

urinalysis

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6
Q

what are some symptoms of dermatomyositis?

A
Photosensitive erythema - usually scalp and periocular 
Shawl sign 
Heliotrope rash 
Gottron's papules 
Ragged cuticles
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7
Q

Which antibody in dermatomyositis is associated with gottrons papules?

A

Anti Jo-1

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8
Q

Which antibody in dermatomyositis is associated with interstitial lung disease and digital ulcers/ischemia?

A

Anti-MDA5

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9
Q

Which antibody in dermatomyositis is associated with malignancy in adults?

A

Anti-p155

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10
Q

Which antibody in dermatomyositis is associated with necrotising myopathy?

A

anti-SRP

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11
Q

name 2 other antibodies in dermatomyositis

A

Anti-SAE - +/- amyopathic

Anti-p140 - juvenile, associated with malignancy

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12
Q

what test are carried out if dermatomyositis is suspected?

A
Muscle biopsy - main test 
Autoantibody profile 
Skin biopsy 
LFT - ALT often increased 
Screening for internal malignancy
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13
Q

State 3 conditions that can be associated with dermatomyositis

A

interstitial lung disease
digital ischemia
malignancy

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14
Q

___Is a manifestation of small vessel vasculitis

A

purpura

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15
Q

State 4 manifestations of medium vessel vasculitis

A

digital necrosis
retiform purpura and linear ulcers
Subcutaneous nodules along blood vessels
Livedo reticularis

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16
Q

What are the symptoms and signs of IgA Vasculitis?

A

Skin - purpura on buttocks/legs
Arthralgias
GI - abdominal pain, meleana
IgA associated glomerulonephritis (hematuria, proteinuria)

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17
Q

What are the symptoms/signs of Granulomatosis with Polyangiitis (GPA)

A

Upper respiratory tract - sinusitis, otitis media
Lower respiratory tract - hemoptysis, cough, dyspnea
Small vessel manifestation - purpura
Medium vessel manifestations
Pauci-immune glomerulonephritis

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18
Q

__ is a systemic disorder most commonly affecting the lungs. Histology involves non-caseating epithelioid granulomas

A

sarcoidosis

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19
Q

what are some symptoms of sarcoidosis

A

Dry cough, dyspnea
Lupus pernio - skin lesions on face
Erythema nodosum - inflammation of subcutaneous fat in legs
KEY findings = Hilar lymphadenopathy - CXR
Papules on skin

UGLIER = (uveitis), Granulomas, lupus pernio, interstitial fibrosis, erythema nodosum (RA)

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20
Q

what is included in the diagnostic criteria for DRESS?

A

Fever
Lymphadenopathy ⩾ 2 sites, > 1cm
Circulating atypical lymphocytes
Peripheral hypereosinophilia
Internal organs involved - Liver most common(hepatitis)
Negative ANA, Hepatitis / mycoplasma, chlamydia

Skin involvement:
>50% BSA
Cutaneous eruption suggestive of DRESS e.g. facial oedema
Biopsy suggestive of DRESS

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21
Q

how do you treat dress?

A

stop drugs, start corticosteroids

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22
Q

What accounts for most fatalities in DRESS

A

fulminant liver failure

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23
Q

signs and symptoms of shnitzler syndrome?

A

recurrent urticarial rash - resolves with brownish hyperpigmentation.
Recurrent fever above 40°C
Bone or joint pain (especially over the ilium or tibia)
Raised monoclonal IgM
Organomegaly - Lymphadenopathy, hepatomegaly or splenomegaly
Neutrophilia
Elevated acute phase reactants or abnormal bone imaging

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24
Q

What is the treatment for schnitzler syndrome?

A

Mild - colchicine

Severe - anakinra

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25
Q

____ is a multiorgan disease affecting 10-80% of allogeneic HSCTs. It can cause a rash including face and acral involvement as well as GI effects (diarrhea, abdominal pain) and Liver effects (elevated bilirubin/jaundice, elevated LFTs)

A

Graft versus host disease

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26
Q

describe the pathophysiology of graft versus host disease

A

donor-derived T-lymphocyte activity against antigens in an immunocompromised recipient

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27
Q

Itching without a rash is known as___.

A

pruritus

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28
Q

name some causes of pruritus

A
Hematological causes: lymphoma, polycythemia - FBC, LDH, Ureamia - renal profile 
Cholestasis - test LFTs 
Iron deficiency or iron overload - test ferritin 
HIV/Hepatitis A/B/C
Cancer 
Drugs - opiates 
Psychogenic 
Pruritus of old age 
(XR chest to check for lymphadenopathy)
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29
Q

____ ___ develops from constant rubbing or scratching in pruritus

A

nodular prurigo

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30
Q

___ ___ is a manifestation of plasma cell dyscrasia

A

systemic amyloidosis

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31
Q

What symptoms, excluding skin findings, are common in systemic amyloidosis?

A

Weight loss, Fatigue

**parasthesias - e.g carpal tunnel syndrome
**Dyspnea - restrictive cardiomyopathy - can progress to heart failure
Syncopal attacks
**hypertrophy of muscles - e.g macroglossia

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32
Q

Which investigations are carried out for systemic amyloidosis?

A

Biopsy of abdominal fat/rectal mucosa

SAP scan

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33
Q

State cutaneous manifestations of systemic amyloidosis

A

Racoon sign - periocular purpura
Papules can also occur in other places - face, neck, scalp, anogenital region, digits
Skin involvement ONLY in 25% of cases

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34
Q

What are the symptoms of scurvy?

A

Spongy gingiva with bleeding and erosion
Skin - petechiae, ecchymosis, follicular hyperkeratosis
Corkscrew hairs with perifollicular hemorrhage

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35
Q

___ results from protein deficiency

A

kwashiokor

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36
Q

state some skin changes seen in kwashiokor

A

Superficial DEQUAMATION
Sparse, dry hair
Soft, thin nails
Cheilitis

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37
Q

state some systemic features seen in kwashiokor

A
Hepatomegaly
Bacterial / fungal infections
Diarrhoea
Loss of muscle mass
Oedema
Failure to thrive
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38
Q

In a Zinc deficiency, what triad is usually seen? When not acquired, what is the genetic cause of deficiency?

A

Dermatitis, Diarrhoea, Depression

Genetic - SLC39A4

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39
Q

In what locations is dermatitis commonly seen in a zinc deficiency and what are some common cutaneous manifestations?

A

Perineal, perioral, acral

Erythema, Scale-crusts, Erosions, Alopecia, Stomatitis, Conjunctivitis

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40
Q

state a role of zinc in the body

A

Wound healing, antioxidant

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41
Q

Severe deficiency of what vitamin leads to pellagra? What 4 “Ds” are seen in pellagra?

A
Vitamin B3 (niacin) 
Diarrhea, Dermatitis, Dementia, Death
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42
Q

State some cutaneous manifestations of vitamin B3 deficiency

A

Photodistributed erythema/hyperpigmentation - classically dorsal surface of hands and on face
“Casal’s necklace”
Glossitis and cheilitis
Painful fissures of palms and soles

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43
Q

Flushing, diarrhea, difficulty breathing, hypotension are all signs of ____ ___ where 5HT is released into the bloodstream

A

Carcinoid syndrome

Flushing only present in 25% of cases

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44
Q

What is the difference between SJS and TEN?

A

SJS affects < 10% of the body. TEN affects > 30. Overlap in between

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45
Q

What are the symptoms in SJS/TEN

A

Prodromal - flu like symptoms
Skin lesions - macules, erythema, blisters, atypical targetoid
Blisters merge and sheets of skin detach
nikolsky +ve

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46
Q

What is the main cause of SJS and TEN

A

drugs

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47
Q

What are the main complications of SJS/TEN?

A

Death - 30%
Dehydration
Blindness
eroded GI tract - ulceration, perforation
interstitial pneumonitis, renal tubular necrosis
Multiple organ failure - liver and heart failure
hypothermia/hyperthermia, neutropenia

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48
Q

What are some differentials for SJS/TEN?

A

Staphylococcal scalded skin syndrome (SSSS)
Thermal burns
Cutaneous graft versus host disease

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49
Q

__ is generalized erythema affecting >90% of BSA

A

erythroderma

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50
Q

What are the causes of erythroderma?

A

Drug reactions
Lymphoma - sezary syndrome
Skin conditions - psoriasis, atopic eczema
Idiopathic (25-30%)

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51
Q

State some complications of erythroderma

A

thermoregulatory problems
Protein and fluid loss
Sepsis risk
Tachycardia, peripheral edema

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52
Q

Prurigo means __ __

A

itchy spots

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53
Q

xerosis means _ __

A

dryness

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54
Q

___ is a condition where calcium blocks the arteries. Patients can get Retiform purpura and ulcers.

A

calciphylaxis

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55
Q

describe some cutaneous signs of CKD

A

Conjunctival pallor, hair thinning (anemia)
Excoriatons, Prurigo - high urea in the blood
Calciphylaxis
Half and half nails
Manifestations corresponding to underlying cause of kidney disease such as:
SLE
ANCA-associated vasculitis
Viral warts, skin cancer (immunosuppression following kidney transplant)
Nephrogenic systemic fibrosis
Xerosis
Perforating disorder

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56
Q

Describe some cutaneous signs of Chronic Liver Disease

A
Muehrcke’s lines 
Terry’s nails (mostly white with distal dark band)
Jaundice
Spider telangiectasia
Palmar erythema 
Porphyria cutaneous tarda 
Clubbing 
Excoriations, prurigo
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57
Q

_____ _____ can occur in the setting of Diabetes Mellitus . It is characterised by red-brown plaques with pale or atrophic centres. It is treated with __

A

Necrobioisis lipoidica

steroids

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58
Q

State some cutaneous manifestations of diabetes

A
Terrys nails 
Granuloma annulare 
Xerosis 
Xanthelesma & Xanthomata 
Neuropathic ulcers 
Acanthosis nigricans - dry dark patches of skin usually in armpits, neck, groin 
Skin infections
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59
Q

Eruptive xanthomas are common in __

A

hyperlipidemia

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60
Q

Pretibial myxoedema is seen in what endocrinological condition?

A

Graves disease

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61
Q

Hyperpigmentation of skin and gums is seen in what endocrinological disorder?

A

Addisons disease

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62
Q

Acne can be a sign of which endocrinological disorders?

A

cushings
acromegaly
pcos

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63
Q

Cutis gyrata verticis can be a sign of which disorder?

A

Acromegaly

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64
Q

List of cutaneous signs of systemic disease - in this case signs of Immunosuppression:

A
Severe seborrhoeic dermatitis
Extensive viral warts 
CMV ulceration 
Eosinophilic folliculitis 
Norwegian scabies 
Bacillary angiomatosis
Severe psoriasis 
Penicillinosis
Tinea corporis & faciei
Cryptococcosis 
Kaposi sarcoma
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65
Q

what are the symptoms of HIV infection?

A

Seroconversion stage can get many types of rashes - ERYTHEMA MULTIFORME UTICARIA, MORBILLIFORM RASH, oral/genital ulceration
persistent or atypical manifestations of common infections
Severe manifestation of common dermatoses - e.g. psoriasis, seborrheic dermatitis
Itch
Eosinophilic folliculitis

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66
Q

State some cutaneous manifestations of inflammatory bowel disease

A
Pyoderma gangrenosum 
Panniculitis (erythema nodosum) 
Orofacial granulomatosis - lips, face or insides of mouth swell
Aphthous ulceration 
Hidradenitis suppuritiva 
Associated with psoriasis and pemphigoid
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67
Q

State some cutaneous manifestations of celiac disease

A

Dermatitis herpetiformis - itchy blisters of extensor surfaces

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68
Q

___ ___ causes inflamed nodes, abscesses, lumps in intertriginous zones, especially axillary anogenital and inframammary area

A

Hidradenitis suppurativa

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69
Q

State 3 causes of pyoderma gangrenosum

A

IBD, leukemia, seronegative arthritis

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70
Q

Groin metastases are common in __ carcinoma

A

prostatic

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71
Q

Which skin symptom can be a symptom of breast cancer?

A

Peau d’orange (breast location)

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72
Q

Name 5 skin infections that Staphylococcus aureus can cause:

A

Ecthyma
Impetigo
Cellulitis
Folliculitis ->abscess: furuncles, carbuncles

Staphylococcal scalded skin syndrome SSS

Can also superinfect other dermatoses (e.g. atopic eczema, HSV, leg ulcers)

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73
Q

Name 5 skin infections that Staphylococcus aureus can cause:

A

(Ecthyma, Impetigo, Cellulitis)

FOLLICULITIS ->abscess: furuncles, carbuncles

Staphylococcal scalded skin syndrome SSS

TOXIC SHOCK SYNDROME

Can also superinfect other dermatoses (e.g. atopic eczema, HSV, leg ulcers)

74
Q

Name 5 skin infections causes by Streptococcus pyogenes

A

(Ecthyma, Impetigo, Cellulitis)

ERYSIPELAS
SCARLET FEVER
NECROTISING FASCIITIS
Can also superinfect other dermatoses (e.g. leg ulcers)

75
Q

What enables staphylococcus aureus to infect wounds? Name one of its virulent exotoxins

A

Has receptors that allow it to bind to fibrin at wound sites (also in dermatitis)

Panton Valentine Leukocidin

76
Q

Streptococcus pyogenes is ___ hemolytic. It has an __ protein along with hyaluronic acid __ which inhibit ___. It also produces ____ exotoxins.

A
B hemolytic 
M protein 
Capsule 
Phagocytosis 
Erythrogenic
77
Q

What are the 2 main causes of folliculitis?

A

Infectious - S. aureus

Non-infectious - eosinophilic folliculitis associated with HIV

78
Q

How do you treat folliculitis?

A

Antibiotics, incision and drainage for furunculosis

79
Q

What are the risk factors for recurrent staphylococcus aureus infections?

A

Abundant in nasal flora

Immune deficiency - e.g. Diabetes Mellitus, AIDS, hyper IgE syndrome, hypogammaglobulinemia

80
Q

Sign and symptoms of PVL staphylococcus aureus infection?

A

Recurrent and painful abscesses, Folliculitis, Cellulitis
MORE THAN 1 SITE, present in contacts

Extracutaneous:
NECROTISING PNEUMONIA
NECROTISING FASCIITIS
PURPURA FULMINANS

81
Q

What are the 2 key effects of PVL toxin?

A

Leukocyte destruction and tissue necrosis

82
Q

What 5 things increase your risk of PVL s.aureus infection

A
  1. close contact
  2. contaminated items
  3. crowding
  4. cleanliness
  5. cuts and grazes
83
Q

How do you treat a PVL s.aureus infection?

A

Antibiotics

Decolonisation:
- Chlorhexidine body wash for 7 days
- Nasal application of mupirocin ointment 5 days
Treatment of close contacts

84
Q

What is cellulitis? What are the symptoms? What causes it?

A

Infection of DEEPER DERMIS and SUBCUTANEOUS tissue

Tender swelling, BLANCHING erythema, oedema, ILL defined
Strep pyogenes and S. aureus

85
Q

What is impetigo? What are the symptoms?

A

Superficial skin infection = EPIDERMIS
Honey-coloured crusting
Usually affects face (perioral, nares, ears)

86
Q

Differentiate between the different types of impetigo

A

non - bullous: caused by s pyogenes

Bullous: caused by s.aureus. Contribution of exfoliative toxin causes FLUID FILLED BLISTERS Toxin targets desmoglein 1.

87
Q

In what setting does impetiginization occur? What causes it?

A

Atopic dermatitis

S.aureus -> gold crust

88
Q

What is ecthyma and how does it present?

A

Severe form of impetigo

Thick crust overlying a punched out ulceration surrounded by erythema

Usually on lower extremities

89
Q

Which groups are susceptible SSS? And what causes it?

A

INFANTS & IMMUNOCOMPROMISED

Exfoliative toxin from s.aureus

90
Q

What are the symptoms of SSS?

A

Infection occurs at distal site e.g. conjuctivitis

Diffuse tender erythema -> flaccid bullae→ sloughing of intraepidermal layer of skin (no scar)

91
Q

What are the symptoms of toxic shock syndrome?

A

Fever >38.9
Shock (hypotension)
Diffuse ERYTHEMA, erythema of mucus membranes (e.g EYES)

Organ involvement eg. liver
Hematologic (platelets <100 000/mm3)

DESQUAMATION predominantly of palms and soles 1-2 weeks after resolution of erythema

92
Q

What causes toxic shock syndrome?

A

Exotoxin TSST-1 from s.aureus

93
Q

How does Blistering Distal Dactylitis manifest?

A

1 or more tender superficial bullae on erythematous base on the volar fat pad of a finger

Toes may rarely be affected
typically young children
strep pyogenes or s.aureus

94
Q

What are the symptoms of Erysipelas? What causes it?

A

Involves UPPER DERMIS
PAINFUL. Presents as erythematous SHARPLY demarcated plaque

FEVER (Malaise, fever, headache)

+/- SUPERFICIAL LYMPHATICS and BLISTERING

Strep. Pyogenes

95
Q

What are some symptoms of scarlet fever? What causes it?

A

Fever, sore throat, headache. Blanching, sandpaper-like body rash

UPPER RESPIRATORY TRACT INFECTION with erythrogenic toxin-producing Streptococcus pyogenes

96
Q

what are some complications of scarlet fever?

A

otitis, mastoiditis, sinusitis, pneumonia, myocarditis, hepatitis, meningitis, rheumatic fever, acute glomerulonephritis

97
Q

Necrotising fasciitis is usually ___ or involves ____ as the only bacteria. Treatment is broad spectrum antibiotics and ___ ____

A

Polymicrobial (often anerobes)
S.pyogenes
Surgical debridement

98
Q

What is the condition called when necrotising fasciitis spreads to scrotum?

A

Fournier’s Gangrene

99
Q

Cutaneously, how does anthrax manifest? What bacteria causes it?

A

PAINLESS necrotic ulcer with surrounding oedema and regional lymphadenopathy (with PAIN in lymph nodes)

Bacillus anthracis.

100
Q

Cutaneously, how does erythrasma manifest? What causes it?

A

Well demarcated patches in intertriginous areas. initially pink -> Become brown and scaly
Infection of Corynebacterium minutissimum

101
Q

Cutaneously, how does pitted keratolysis manifest? What causes it?

A

Pitted erosions of soles
Caused by Corynebacterium
Treated with topical clindamycin.

102
Q

What Mycobacterium causes indolent granulomatous ulcers in healthy people? A risk factor is being an aquarium handler and has sporotrichoid spread?

A

mycobacterum marinum

103
Q

What mycobacterium is an important cause of limb ulceration in Africa (Buruli ulcer) or Australia (Searle’s ulcer)?

A

mycobacterium ulcerans

104
Q

Which two mycobacteria cause infection following puncture wounds, tattoos, skin trauma or surgery?

A

Mycobacterium chelonae & abscessus

105
Q

Mycobacterium ____ is an obligate intracellular bacteria. It predominantly affects skin & nerves, but can affect any organ

A

leprae

106
Q

Mycobacterium is a common cause of infection in __ states

A

immunosupressed

107
Q

Distinguish between the two types of leprosy

A

Lepromatous leprosy:
Multiple lesions
Sensation and sweating normal (early on)

Tuberculoid leprosy:

  • SOLITARY or FEW: elevated borders atrophic center, sometimes annular
  • HAIRLESS, ANHIDROTIC, NUMB
108
Q

Describe 3 ways that cutaneous TB may be acquired

A

Exogenously -> e.g. tuberculosis verrucosa cutis

Contiguous endogenous spread -> seen in scrofuloderma and periorificial tuberculosis

Haematogenous/lymphatic endogenous spread -> seen in lupus vulgaris, miliary tuberculosis, gummas

109
Q

What diagnostic tests are useful for cutaneous TB?

A

Histology - ZN stain
culture/PCR
Interferon gamma release assay

110
Q

What bacteria causes Erysipeloid? What is the typical exposure? What are the symptoms?

A

Erysipelothrix rhusiopathiae - after handling contaminated raw fish or meat.

Erythema and oedema of the hand

111
Q

___ ______ is associated with hot tub use, swimming pools and depilatories, wet suits.
It appears 1-3 days after exposure, as a diffuse truncal eruption of erythematous papules. Usually self limited

A

Pseudomonal folliculitis -> caused by pseudomonas aeruginosa

112
Q

The difference between ecthyma and ecthyma gangrenosum is that ecthyma gangrenosum is multiple ulcers, is caused by ___ ____ and usually occurs in neutropenic patients.

A

pseudomonas aeruginosa

113
Q

What causes Tularaemia? What are the symptoms

A

Zoonotic bacteria: Francisella tularensis

Handling infected animals (squirrels and rabbits), Tick bites, Deerfly bites

PAINFUL ulcer and PAINFUL regional lymphadenopathy

Systemic symptoms: Fever, chills, headache, malaise

May have local cellulitis

114
Q

what causes Lyme disease and how does the disease progress?

A

Bite form Ixodes tick infected with Borrelia burgdorferi

Stage 1 - flu like symptoms, erythema migrans (annular erythema/”bulls-eye”)

Stage 2 - secondary lesions, arthritis, cardiits, Neuroborreliosis (Facial palsy, Aseptic meningitis, Polyradiculitis)

115
Q

What causes syphilis and what does primary syphilis look like?

A

Treponema pallidum

Chancre -PAINLESS ulcer. Classically on PENIS. + PAINLESS regional lymphadenopathy

116
Q

What are the symptoms of secondary syphilis?

A

Maculopapular rash which also involves PALMS AND SOLES

Condylomata lata (painless, wart like WHITE lesions) - genitals, mouth, perineum

Small oral ulcers e.g. on tongue, mucous patches

Alopecia
Lymphadenopathy
Hepatospleenomegaly

117
Q

symptoms of tertiary syphilis?

A

Gumma Skin lesions:

  • plaques
  • Extend peripherally while - central areas heal with scarring and atrophy
  • Mucosal lesions extend to and destroy the nasal cartilage

Neurosyphilis - (general paresis or tabes dorsalis (broad-based ataxia))

Cardiovascular disease - stroke without hypertension

118
Q

How do you treat syphilis?

A

IM benzylpenicillin or (oral tetracycline)

119
Q

What is lues maligna? When does it typically occur?

A

Rare manifestation of SECONDARY syphilis
Pleomorphic skin lesions with pustules, NODULES AND ULCERS with necrotising vasculitis
More frequent in HIV manifestation

120
Q

Differentiate between how the 2 types of herpes simplex viruses are spread

A

HSV1 - saliva, secretions

HSV2 - sexual contact

121
Q

What are the symptoms of a herpes simplex virus infection?

A

Tingling in the area, grouped blisters, crusting and resolution, can be asymptomatic
Latent, can reactivate

122
Q

How does eczema herpeticum manifest? What causes it?

A

Cluster of itchy blisters/punched out erosions
often seen as a complication of atopic dermatitis/eczema.
Caused by HSV1 or HSV2
Emergency - can complicate into encephalitis

123
Q

What is herpetic whitlow?

A

Pain, swelling of digits

HSV 1>2

124
Q

How does herpes gladiatorum manifest?

A

HSV 1 involvement of cutaneous site reflecting sites of contact with another athlete’s lesions
Contact sports e.g. wrestling

125
Q

What causes neonatal herpes? What is a major complication?

A

Herpes simplex virus exposure during vaginal delivery

Encephalitis (seizures, poor feeding)

126
Q

How do you diagnose herpes simplex virus infection?

A

Swab -> PCR

127
Q

How do you treat HSV infection?

A

Oral acyclovir or valacyclovir

128
Q

How does a Varicella zoster virus reactivation present cutaneously? Feared complication?

A

single or multi dermatomal lesions
Complication -> blindness
Caused by HHV-3

129
Q

What causes Roseola infantum? How does it manifest?

A

HHV6 and 7 in children
High fever -> followed by diffuse macular rash spreading from trunk to extremities
Self-limited

130
Q

What causes Moloscum contagiousum? And how does it manifest?

A

Poxvirus

Flesh-coloured papule with central umbilication

131
Q

What causes Erythema infectiosum? How does it manifest

A

parvovirus B19
Slapped cheeks rash in children for 2-4 days
Then reticulated (lacy) rash of chest and thighs in 2nd stage of disease

132
Q

What causes Orf? How does it manifest?

A

Parapoxvirus. Direct exposure to sheep or goats
Dome-shaped, firm bullae that develop an umbilicated crust.
Usually develop on hands and forearms
self-limited

133
Q

What organisms cause warts?

A

hpv

134
Q

What causes hand foot and mouth disease? How does it manifest?

A

coxsackie virus or echovirus (higher incidence or neurologic complications)
Vesicles, macules on buccal mucosa, tongue, palate and pharynx
Also on hands and feet

135
Q

Other than drugs, which viruses cause morbilliform (measles-like) eruptions?

A

Measles, Rubella, EBV, CMV, HHV6 & HHV7 cause morbilliform (measles-like) eruptions
Leptospirosis
Rickettsia

136
Q

Causes of petechial/purpuric eruptions?

A

Coagulation abnormalities - TTP, ITP, DIC
Vasculitis
Infections
Viruses - (Hepatitis B, CMV, Rubella, Yellow fever, Dengue fever, West nile virus)
Bacterial (BREN) - (Borrelia, Rickettsia, Neisseria, Endocarditis)
Other infections - (Plasmodium falciparum, Trichinella)
Other - (TEN, Ergot poisoning, Raynauds)

137
Q

How does Gianotti-Crosti Syndrome manifest? What causes it?

A

Eruption of papules on the outer extremities in a symmetrical pattern
Some Viruses. It is self-limited

138
Q

What causes Pityriasis versicolor? How does is it present?

A

Malassezia spp. Hot humid weather

Hypopigmented, hyperpigmented or erythematous macular eruption +/- fine scale

139
Q

How do you treat pityriasis versicolor?

A

topical azole

140
Q

___ are fungi that live on keratin. Trichophyton ____ causes the most fungal infections
Trichophyton ____ causes the most tinea capitis

A

Dermatophytes
Rubrum
Tonsurans

141
Q

Trichophyton tonsurans which causes the most tinea capitis can manifest with ___ formation. Tinea capitis is also associated with ___

A

Kerion

Lymphadenopathy

142
Q

Tinea unguium is also known as ___

A

onychomycosis

143
Q

Describe the different ways in which tinea pedis can manifest

A

Interdigital

Diffuse scaling of plantar surface of foot

144
Q

what are id reactions?

A

Aka Dermatophytid reactions
Inflammatory reactions at sites distant from the associated dermatophyte infection
May include urticaria, hand dermatitis, or erythema nodosum
Likely secondary to a strong host immunologic response against fungal antigens

145
Q

Follicular abscess produced when dermatophyte infection penetrates the follicular wall into surrounding dermis is known as?

A

Majocchi granuloma

146
Q

Name a condition that predisposes someone to candidiasis. Describe how the condition presents

A

Diabetes mellitus

Erythema oedema + discharge. Usually an intertriginous infection

147
Q

Give examples of deep fungal infections and identify how they appear

A

Sporotrichosis - along lymphatics. Caused by sporothrix schenckii and other fungi
Chromomycois
Mycetoma (Madura foot)

148
Q

Name 4 different systemic fungal infections and identify how they appear

A
Histoplasmosis
Blastomycosis 
 Coccidiodomycosis
Paracoccidoiodomycosis
(also penicillinosis)
149
Q

What causes aspergillosis? How does it present?

A

Aspergillus fumigatus - RESPIRATORY pathogen. Septate hyphae that branch at 45 degrees
Papules with NECROTIC base and surrounding halo (a differential in necrotizing lesions)
May invade blood vessels causing thrombosis and infarction
May extend into cartilage, bone and fascial planes

150
Q

What causes mucormycosis and what is the main risk factor for this condition?

A

Mucor and Rhizopus spp. (and others)

DKA

151
Q

How does mucormycosis present? How do you treat it?

A
Fever, headache 
Facial oedema, facial pain 
Orbital cellulitis 
Cranial nerve dysfunction 
Proptosis 
Treat with debridement and antifungals
152
Q

What are some opportunistic fungal infections causing skin disorders?

A

Candidiasis
Aspergillus fumigatus
Mucor and Rhizopus
Sporothrix schenckii

153
Q

what are the symtoms of scabies?

A

red to flesh-coloured pruritic papules
Affects interdigital areas of digits, volar wrists, axillary areas, genitalia
diagnostic burrow consisting of fine white scale is often seen
Norwegian scabies immunocompromised

154
Q

how do you treat scabies?

A

permethrin, oral ivermectin

Two cycles of treatment are required

155
Q

Distinguish between the different types of lice infestation

A

Head louse:
Pediculus humanus capitis
- Treatment: malathion, permethrin, or oral ivermectin
Body louse:
Lives and reproduces in clothing – leaves to feed; rarely found on skin
Pruritic papules & hyperpigmentation
Eliminated through cleaning or discarding clothes
Pubic Louse:
Phithrus pubis aka crabs; three pairs of legs
Eggs found on hair shaft, also found in occipital scalp, body hair, eyebrow and eyelash, axillary hair
Treatment: malathion / permethrin, oral ivermectin

156
Q

What are Cimex lectularius and what do they cause?

A

Bed bugs -> bites -> itchy weals around central punctum

157
Q

What is the most common skin cancer? What is the second most common ?

A

Most common - basal cell carcinoma

Squamous cell carcinoma

158
Q

What is a melanoma?

A

Malignant tumour of Melanocytes

High metastatic potential. >75% of skin cancer deaths

159
Q

How does a melanoma present/look?

A

A - asymmetrical
B - border irregularity
C - colour variation
D - diameter >6mm
E - evolution - change in size, shape, colour
Can arise on mucosal surfaces too e.g. oral, conjunctival vaginal

160
Q

What are risk factors for a melanoma?

A

Genetic factors:
Family history - CNKN2A mutations, MC1R variants
Light skin
Red hair
DNA repair defects - xeroderma pigmentosum

Environmental
Sun exposure
Immunosuppression

Phenotypic
>100 or atypical nevi (ugly duckling sign) NOT just presence of nevi

161
Q

What are the subtypes of melanomas? What are the key features of each?

A

Superficial spreading
Most common - can be identified using ABCDE
Initial horizontal growth then vertical
Regression visible as grey, hypo- or depigmentation

Nodular
2nd most common
blue/black, sometimes pink
Aggressive.Develops rapidly - only vertical growth. LACKS RADIAL GROWTH

Lentigo maligna
Lentigo maligna = Brown to black macule with colour variation. Slow growing. Only 5% become invasive -> lentigo maligna melanoma
Sun damaged skin - usually face

Acral lentiginous
least common
Occurs on palms and soles (can appear ulcerated, scaly) and nail apparatus
Affects all skin types equally. Higher proportion than other types of melanomas in african-americans and asians !!!!!
Unclassifiable

162
Q

What signalling pathway regulates cellular proliferation, growth and migration? What mutations in this pathway result in Melanomas?

A

Activation of MAPK pathway:

  • KIT mutations (seen in some acral and mucosal melanomas)
  • Activation mutations in BRAF, NRAS
  • Mutations in CDKN2A which encodes p16 (tumour suppressor gene)
163
Q

____ is a natural inhibitor of T-cell activation and prevents host immune response, leading to melanoma development. Immunotherapy is based on blocking it. Name a drug used for this

A

CTLA-4

Ipilimumab

164
Q

Other than CTL4-A inhibitors, what other drug is used in immunotherapy for melanomas?

A

Checkpoint inhibitors - PD-1, PDL1 inhibitors (nivolumab)

165
Q

What investigation is carried out for suspected melanoma?

A

Dermoscopy. Should not be considered in isolation. If in doubt/ suspected melanoma-> excise with wide margins

166
Q

What stage of melanomas is sentinel lymph node biopsy offered for?

A

pT1b +

167
Q

What blood component is a prognostic factor in metastatic melanoma?

A

LDH

168
Q

State 4 conditions that can result from keratinocyte dysplasia/carcinoma

A

Actinic keratoses -> can lead to squamous cell carcinoma. But LOW risk
Squamous cell carcinoma (potential for metastases)
Browns disease -> squamous cell carcinoma in situ
Basal cell carcinoma (invasive but RARELY metastasize)

169
Q

What are some risk factors for keratinocyte carcinomas ( more common in MEN)?

A
Organ transplantation (immunosuppressive drugs) 
Chronic non-healing wounds
170
Q

How does actinic keratoses look/present

A

Erythematous or brownish papules/plaques
Or hyperkeratosis or both
Confined to epidermis

171
Q

How do you treat actinic keratoses & bowens disease?

A

5-fluorouracil cream, cryotherapy, Imiquimod cream
Photodynamic therapy, curettage and cautery.
Excision

172
Q

How does a squamous cell carcinoma look/present?

A

Red/skin colour plaques - may ulcerate and produce keratin, crust or bleed
May be Papules, may be exophytic(sticking out)
Commonly on face, lower lip, ears, hands
Common in immunosuppressed

173
Q

___ are dome-shaped nodules, they grow rapidly and spontaneously regress. They are a variant of SCC and commonly occur on face/sun exposed areas

A

Keratoacanthoma

174
Q

What are the main subtypes of basal cell carcinoma? What are the key features of each?

A

Nodular
Most common
Shiny pearly papule, blood vessels

Superficial
Erythematous plaque

Morphoeic
Slightly elevated or depressed area. Resembles a scar
More aggressive behaviour - local destruction

Infiltrative - aggressive

Basisquamous
hyperkeratosis/scaling can be seen

Micronodular
More destructive than nodular

175
Q

What are the 2 most common cutaneous T-cell lymphomas ? typically affect older adults

A

mycosis fungoides - common. 50% of primary cutaneous lymphomas
Sezary syndrome - rare
Typically affect older adults

176
Q

What are the features of mycosis fungoides Hows do you diagnose it?

A

Erythematous, scaling patch sage -> Plaque stage -> tumour stage
skin biopsy. may take years

177
Q

What are the features of Sezary syndrome?

A

Erythroderma
Generalised lymphadenopathy
Presence of neoplastic T-cells (Sezary cells) in the skin, lymph nodes and peripheral blood

178
Q

How do you treat sezary syndrome?

A

Requires Systemic treatment

Can also use Extracorporeal photopheresis

179
Q

What causes Kaposi sarcoma? How does it appear? How do you treat it?

A

HHV8. endemic or related to immunosuppresion
pink-> dark violets patches, plaques, nodules, polyps
chemotherapy and/or radiotherapy, excision

180
Q

What causes merkel cell carcinoma?

A

80% = polyomavirus
UV exposure
Does NOT arise from merkel cells but cells similar