7.1 - The skin in systemic disease Flashcards

1
Q

What different causes of dermatological conditions are there? (9)

A
  • idiopathic
  • neoplastic
  • infection
  • inflammatory
  • drug-induced
  • autoimmune
  • traumatic
  • metabolic
  • genetic
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2
Q

What are examples of clinical assessments used in dermatology? (5)

A
  • blood tests (FBC, renal profile, LFTs, inflammatory markers, autoimmune serology)
  • microbiology (viral/bacterial serology, swabs for bacteria C&S, viral PCR, tissue culture/PCR)
  • imaging (internal organ involvement, vascular supply)
  • skin biopsy (microscopy)
  • specific (urinalysis, nerve conduction studies, endocrine investigations etc)
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3
Q

What is a punch biopsy?

A
  • biopsy of skin done under local anaesthetic
  • cells taken and examined for inflammatory patterns/cell abnormalities to look for neoplasia
  • can also look for autoantibodies through immunofluorescence
  • can also be sent for tissue culture
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4
Q

What are the two main groups of lupus erythematosus?

A
  • systemic lupus erythematosus
  • cutaneous (discoid) lupus erythematosus
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5
Q

How can the diagnostic criteria for systemic lupus erythematosus be grouped? (4)

A
  • mucocutaneous
  • haematological
  • immunological
  • joint + organ involvement
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6
Q

What are the mucocutaneous diagnostic criteria for systemic lupus erythematosus? (4)

A
  • cutaneous lupus - acute (e.g. chilblains and photodistributed erythematosus rash)
  • cutaneous lupus - chronic
  • oral ulcers
  • alopecia
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7
Q

What are the haematological diagnostic criteria for systemic lupus erythematosus? (3)

A
  • haemolytic anaemia
  • thrombocytopenia
  • leukopenia
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8
Q

What are the immunological diagnostic criteria for systemic lupus erythematosus? (6)

A
  • ANA
  • anti-dsDNA
  • anti-Sm
  • antiphospholipid
  • low complement
  • direct Coomb’s test
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9
Q

What are the joint and organ involvement diagnostic criteria + other diagnostic criteria for systemic lupus erythematosus? (2 + 2)

A
  • synovitis
  • serositis (pleurisy/pleuritis or pericarditis)
  • renal disorder
  • neurological disorder
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10
Q

What are some manifestations of systemic lupus erythematosus? (6)

A
  • photodistributed rash (sun-exposed)
  • chilblains
  • alopecia
  • livedo reticularis (net-like erythema)
  • cutaneous vasculitis
    • palpable purpura - small vessel cutaneous vasculitis
  • subacute cutaneous lupus (SCLE) - ring-like (annular) plaques
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11
Q

What are some manifestations of cutaneous (discoid) lupus erythematosus? (2)

A
  • discoid lupus erythematosus (often causes scarring)
  • SCLE (subacute cutaneous lupus) - ring-like/annular plaques
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12
Q

What does a ring-like or annular rash on a baby indicate?

A

Immediate diagnosis of neonatal lupus - do ECG as there is 50% risk of heart block

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13
Q

What is dermatomyositis?

A

Autoimmune connective tissue disease

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14
Q

What is dermatomyositis characterised by? (2)

A
  • proximal extensor inflammatory myopathy
  • photodistributed pink-violet rash favouring scalp, periocular regional and extensor surfaces
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15
Q

What are some distinct clinical features of dermatomyositis? (5)

A
  • Gottron’s papules (violaceous red plaques on MCP and DIP joints)
  • ragged cuticles
  • shawl sign (rash of upper trunk)
  • heliotrope rash (erythema of upper eyelids)
  • photosensitive erythema
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16
Q

Does dermatomyositis have subtypes?

A

Yes - subtypes with distinct clinical features that can be predicted by autoantibody profile

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17
Q

What different subtypes of dermatomyositis exist and what clinical features are they associated with? (7)

A
  • anti Jo-1 (fever, myositis, Gottron’s papules)
  • anti SRP (necrotising myopathy)
  • anti Mi-2 (mild muscle disease)
  • anti-p155 (associated with malignancy in adults)
  • anti-p140 (juvenile, associated with calcinosis)
  • anti-SAE (+/- amyopathic)
  • anti-MDA5 (intersitital lung disease, digital ulcers/ischaemia)
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18
Q

What diagnostic tests do we do for dermatomyositis? (6)

A
  • ANA (anti-nuclear AB) - often +ve
  • LFT - ALT often increased
  • CK and EMG (muscle involvement)
  • skin biopsy
  • screening for internal malignancy (imaging and tumour markers)
  • dermatomyositis panel antibodies - subtype
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19
Q

Vasculitis - biopsy for direct immunofluorescence shows perivascular IgA autoantibodies, what is this?

A

IgA vasculitis (Henoch-Schonlein purpura)

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20
Q

What are some manifestations of IgA vasculitis? (5)

A
  • abdominal pain
  • bleeding (GI)
  • arthralgia (joint stiffness)
  • arthritis
  • IgA-associated glomerulonephritis (may develop later, monitor)
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21
Q

What types of vasculitis are small vessels affected by? (2)

A
  • cutaneous small vessel (leukocytoclastic) vasculitis
  • small vessel vasculitis - special types
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22
Q

What are the subclassifications of cutaneous small vessel (leukocytoclastic) vasculitis? (4)

A
  • idiopathic
  • infectious
  • inflammatory (connective tissue disease)
  • medication exposure
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23
Q

What are some subclassifications of small vessel vasculitis (4)

A
  • IgA vasculitis (Henoch-Schonlein)
  • urticarial vasculitis
  • acute haemorrhagic oedema of infancy
  • erythema elevatum diutinum
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24
Q

What types of vasculitis are small and medium vessels affected by? (2)

A
  • cryoglobulinemia
  • ANCA-associated
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25
Q

What are some subclassifications of cryoglobulinemia?

A

Type II & III

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26
Q

What are some subclassifications of ANCA-associated vasculitis? (3)

A
  • EGPA (Churg-Strauss)
  • microscopic polyangiitis
  • GPA (Wegener)
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27
Q

What type of vasculitis is medium vessels affected by, and what are its subclassifications?

A

Polyarteritis nodosa (PAN)

  • benign cutaneous form
  • systemic form
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28
Q

What types of vasculitis are large vessels affected by? (2)

A
  • temporal arteritis
  • Takayasu
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29
Q

What is a small vessel manifestation of vasculitis?

A

Purpura (macular / palpable)

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30
Q

What are the medium vessel manifestations of vasculitis? (3)

A
  • digital necrosis
  • retiform ‘net-like’ purpura ulcers
  • subcutaneous nodules along blood vessels
31
Q

What type of deformity is associated with ANCA-associated vasculitis?

A

Saddle nose deformity

32
Q

What is sarcoidosis?

A

Systemic granulomatous disorder of unknown origin (non-infectious systemic inflammatory disorder in which granulomas infiltrate different organ systems)

33
Q

What can sarcoidosis affect?

A

Can affect multiple organs, most commonly lungs

34
Q

How common are cutaneous (skin) manifestations of sarcoidosis?

A

33%

35
Q

What makes sarcoidosis hard to diagnose?

A

Highly variable - ‘the great mimicker’

36
Q

What are some of the cutaneous (skin) manifestations of sarcoidosis? (5)

A
  • red-brown violaceous papules of face, lips, upper back, neck and extremities
  • lupus pernio (involvement of nose and cheeks, nothing to do with lupus erythematosus despite name)
  • ulcers
  • scar sarcoid
  • erythema nodosum (swollen fat under skin of legs)
37
Q

What does histology of sarcoidosis show?

A

Non-caseating (means no necrosis) epithelioid granulomas

38
Q

What kind of diagnosis is sarcoidosis?

A

Diagnosis of exclusion - must exclude infection e.g. through TB culture/PCR

39
Q

What else must be monitored in sarcoidosis?

A

Internal organ involvement e.g. CXR for lung involvement

40
Q

What does DRESS stand for?

A

Drug Reaction with Eosinophilia and Systemic Symptoms

41
Q

What is DRESS?

A

Rash and systemic upset incorporating haematological and solid-organ disturbances

42
Q

What are the diagnostic criteria for DRESS? (7 - do not need to memorise?)

A
  • fever >38.5
  • lymphadenopathy >/=2 sites, >1cm
  • circulating atypical lymphocytes
  • peripheral hypereosinophilia >0.7x10^9
  • internal organs involved
  • negative ANA, hepatitis/mycoplasma, chlamydia
  • skin involvement
    • > 50% BSA
    • cutaneous eruption suggestive of DRESS
    • biopsy suggestive of DRESS
43
Q

What internal organs are involved in DRESS? (6)

A
  • liver (hepatitis) - most common, majority of deaths associated with this
  • kidneys (interstitial nephritis)
  • heart (myocarditis)
  • brain
  • thyroid (thyroiditis)
  • lungs (interstitial pneumonitis)
44
Q

What do we know about the mechanism for DRESS?

A
  • underlying mechanism not known
  • starts 2-6 weeks after drug exposure
45
Q

What are some common drug triggers for DRESS? (5)

A
  • sulfonamides
  • allopurinol
  • anti-epileptics (lamotrigine, carbamazepine, phenytoin)
  • antibiotics (vancomycin, amoxicillin, minocycline, piperacillin-tazobactam)
  • ibuprofen
46
Q

What can the rash look like in DRESS? (5)

A
  • urticated papular exanthem - widespread papules
  • maculopapular (morbilliform) eruption
  • widespread erythema (erythroderma)
  • head and neck oedema
  • erythema multiforme-like (targetoid lesions)
47
Q

How do we treat DRESS?

A
  • withdrawal of culprit
  • corticosteroids are first line treatment - may require months of treatment
  • mortality 5-10%
48
Q

What kind of disorder is Graft vs Host disease (GvHD)?

A

Multiple-organ disease, alloimmune

49
Q

Who does Graft vs Host disease (GvHD) affect?

A

10-80% of allogenic haematopoietic stem call transplants (HSCT)

50
Q

How do we know if a rash is caused by Graft vs Host disease (GvHD) as opposed to drugs? (3)

A
  • face involvement
  • acral involvement
  • diarrhoea
  • (indicates GvHD more likely)
51
Q

What is the pathogenesis of Graft vs Host disease (GvHD)?

A

Donor-derived T-lymphocyte activity against antigens in an immunocompromised patient

52
Q

What body parts does Graft vs Host disease (GvHD) mainly affect? (3)

A
  • skin
  • liver
  • GI tract
53
Q

What does itching (pruritus) without a rash suggest?

A

Internal cause - something else going on

54
Q

What needs to be considered when there is an itch without a rash? (9)

A
  • haematological causes - lymphoma, polycythaemia
  • uraemia
  • cholestasis
  • iron deficiency or iron overload
  • HIV / hepatitis A/B/C
  • cancer
  • drugs (esp opiates/opioids)
  • psychogenic
  • pruritus of old age
55
Q

What investigations do we do for itching without a rash? (6)

A
  • FBC, LDH
  • renal profile
  • liver function tests
  • ferritin
  • chest X-ray
  • HIV / hepatitis ABC test
56
Q

What do patients develop if they keep itching?

A

Nodular prurigo - skin thickening as a defence mechanism from the scratch

57
Q

What is carcinoid syndrome?

A

When a malignant carcinoid tumour metastasises and secretes 5-HT into system

58
Q

What symptom occurs in 25% of carcinoid syndrome cases?

A

Flushing

59
Q

What are some other symptoms of carcinoid syndrome (apart from flushing)? (3)

A
  • diarrhoea
  • bronchospasm
  • hypotension
60
Q

What is Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS:TEN)?

A

A dermatological emergency!! (Rare)

61
Q

What is the sequence of development of symptoms in Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS:TEN)? (5 steps)

A
  1. prodromal flu-like symptoms
  2. abrupt onset of lesions on trunk, then face/limbs
  3. macules, blisters, erythema - atypical targetoid
  4. blisters then merge and sheets of skin detach ‘like wet wallpaper’
  5. this represents extensive full thickness mucocutaneous (epidermal) necrosis in 2-3 days
62
Q

When is SJS:TEN called SJS and when is it called TEN?

A
  • when <10% of BSA detachment = SJS (<10% mortality)
  • when 10-30% of BSA detachment = SJS/TEN
  • when >30% of BSA detachment = TEN (>30% mortality)
63
Q

What is the pathophysiology of SJS:TEN?

A

Cell-mediated cytotoxic reaction against epidermal cells

64
Q

What is SJS:TEN mostly caused by?

A
  • drugs cause >80% of cases
    • antibiotics e.g. beta-lactams, sulfonamides
    • allopurinol
    • anti-epileptics e.g. phenytoin, carbamazepine, lamotrigine
    • NSAIDs
  • may be started up to 3 weeks prior to onset of rash
65
Q

What are the differential diagnoses for SJS:TEN? (3)

A
  • staphylococcal scalded skin syndrome (SSSS)
  • thermal burns
  • cutaneous Graft vs Host Disease (GvHD)
66
Q

How is the severity of SJS:TEN determined?

A
  • SCORTEN score calculated with criteria: (do not need to memorise)
    • age > 40
    • initial % epidermal detachment
    • serum area + glucose + bicarbonate
    • presence of malignancy
67
Q

What are some complications of SJS:TEN? (9)

A
  • death (overall mortality 30%)
  • blindness
  • dehydration
  • hypothermia/hyperthermia
  • renal tubular acidosis
  • eroded GI tract
  • interstitial pneumonitis
  • neutropenia
  • liver and heart failure
68
Q

What is erythroderma?

A

Generalised erythema affecting >90% BSA (impairs skin function)

69
Q

What can erythroderma manifest as systemically? (5)

A
  • peripheral oedema
  • tachycardia
  • loss of fluid and proteins
  • disturbances in thermoregulation
  • risk of sepsis
70
Q

What can cause erythroderma? (5)

A
  • drug reactions
  • cutaneous T-cell lymphoma (Sezary syndrome)
  • psoriasis
  • atopic eczema
  • idiopathic (25-30%)
71
Q

Describe the management of erythroderma. (6)

A
  • underlying cause (e.g. treat psoriasis, withdraw drug if drug cause, etc)
  • hospitalisation if systemically unwell
  • restore fluid and electrolyte balance, circulatory status and manage body temperature
  • emollients to support skin barrier
  • maybe topical steroids
  • maybe antibiotics
72
Q

What should we be aware of regarding common diseases?

A

A variety of common diseases can also cause skin manifestations, and recognition of these can allow early diagnosis

73
Q

What are some examples of types of systemic diseases that have dermatological manifestations? (7)

A
  • nutritional disorders:
    • scurvy (vitamin C deficiency)
    • Kwashiorkor
  • malignancy
  • chronic kidney disease
  • chronic liver disease
  • endocrine disorders (DM, Graves, Addison’s, acromegaly, Cushing’s, PCOS)
  • GI disease (IBD, Crohn’s, Coeliac)
  • infection
74
Q

Compare SLE vs DLE vs subacute LE.

A
  • SLE - redness of sun-exposed areas (photo-distributed rash)
  • DLE - scars, plaques, can have underlying SLE
  • subacute LE - ring/annular
  • to disregard SLE - negative systems review, no photo-distributed rash, negative antibodies, FBC normal etc