dermatology Flashcards
what does comprehensive assessment along with dermatological diagnostic skills allow?
prevent or reduce internal organ damage by early diagnosis
allow detection of internal malignancy
what are the ways in which the skin can be involved in systemic disease (with examples)?
skin targeted as part of multi-organ systemic disease (e.g. sarcoidosis)
skin displays sign of internal disorder (e.g. flushing in carcinoid syndrome)
“tell-tale” skin conditions suggestive of underlying condition (e.g. Pyoderma gangrenosum in inflammatory bowel disease)
skin disorder may cause secondary internal organ involvement (e.g. high output cardiac failure in erythroderma)
when considering neoplasia, what tests may be done?
imaging - examine for internal organ involvement
biopsy of affected skin
what are the 10 different routes to a diagnosis/categories of causes in diagnosis?
idiopathic
neoplastic
infection
inflammatory
drug-induced
autoimmune
traumatic
metabolic
genetic
what 5 clinical assessments are undertaken in diagnosis?
blood tests
microbiology
imaging
skin biopsy
specific
what blood tests may be done as part of diagnosis?
full blood count
renal profile
liver function tests
inflammatory markers
autoimmune serology
what microbiology may be done as part of diagnosis?
viral / bacterial serology swabs for bacteria C&S, viral PCR tissue culture / PCR
what imaging may be done as part of diagnosis?
internal organ involvement
vascular supply
what skin biopsy may be done as part of diagnosis?
microscopy
what specific clinical assessments may be done as part of diagnosis?
urinalysis
nerve conduction studies
endocrine investigations etc.
how can an interface pattern of inflammation be described?
vacuoles (little white spaces) and lymphocytes along dermal epidermal junction
where is an interface pattern of inflammation seen?
lupus (and others)
what does a line along the dermal epidermal junction in an immunofluorescence assay indicate?
presence of autoantibodies
what are the 2 main groups of lupus erythematosus?
systemic lupus erythematosus cutaneous (discoid) lupus erythematosus (overlap)
what are the mucocutaneous diagnostic criteria for lupus erythematosus?
cutaneous lupus - acute cutaneous lupus -chronic oral ulcers alopecia
what are the haematological diagnostic criteria for lupus erythematosus?
haemolytic anaemia thrombocytopenia leukopenia
what are the immunological diagnostic criteria for lupus erythematosus?
ANA anti-dsDNA anti-Sm antiphospholipid low complement direct Coomb’s test
what are other diagnostic criteria for lupus erythematosus?
synovitis serositis (pleurisy or pericarditis) renal disorder neurological disorder
what are some features appearing on the skin in lupus erythematosus?
chilblains photodistributed (sun-exposed areas) erythematous rash
what are the cutaneous manifestations of systemic lupus erythematosus?
photodistributed rash cutaneous vasculitis manifesting as palpable purpura chilblains alopecia livedo reticularis (net-like pattern of redness) subacute cutaneous lupus (SCLE) - annular/semi-annular scaly erythema photodistributed
what are the typical features of cutaneous (discoid) lupus erythematosus?
scarring noticeable when it’s present on the scalp - results in alopecia as hair follicle unit is replaced by scar tissue may also have subacute cutaneous lupus (SCLE) - annular/semi-annular scaly erythema photodistributed
what is the suspected underlying disorder in a newborn with an annular rash affecting the forehead and zygomatic prominences?
suspected neonatal lupus (associated with Ro antibodies)
what test is needed in a newborn with an annular rash affecting the forehead and zygomatic prominences?
ECG needed - 50% chance of heart block
what is dermatomyositis?
autoimmune connective tissue disease
what is dermatomyositis generally associated with?
proximal extensor inflammatory myopathy (muscle weakness associated)
what are some pathognomonic signs of dermatomyositis?
Gottron’s papules - pink/violet rashes of the metacarpal, phalangeal and interphalangeal joints ragged cuticles erythema along upper trunk in shawl like distribution (“shawl sign”) heliotrope rash around eyes photosensitive erythema
what are the main signs of dermatomyositis?
photo-distributed pink-violet rash favouring scalp, periocular regional and extensor surfaces
how can autoantibody profiles be used in dermatomyositis?
subtypes with clinical features can be predicted by autoantibody profile
what does anti Jo-1 indicate in dermatomyositis?
fever myositis Gottron’s papules
what does anti SRP indicate in dermatomyositis?
necrotising myopathy
what does anti Mi-2 indicate in dermatomyositis?
mild muscle disease
what does anti p155 indicate in dermatomyositis?
associated with malignancy (in adults)
what does anti p140 indicate in dermatomyositis?
juvenile, associated with calcinosis
what does anti SAE indicate in dermatomyositis?
may suggest muscles are spared
what does anti MDA5 indicate in dermatomyositis?
interstitial lung disease digital ulcers/ischaemia
what blood tests need to be done in dermatomyositis?
ANA CK (indicate muscle involvement) skin biopsy LFT (ALT often increased) EMG or MRI screening for internal malignancy
why is IgA vasculitis dangerous?
looks like any other small vessel vasculitis can cause progressive renal failure (follow carefully if haematuria or proteinuria)
what are the types of cutaneous small vessel (leukocytoclastic) vasculitis?
idiopathic infectious medication exposure inflammatory (connective tissue disease
what are the special types of small vessel vasculitis?
IgA Vasculitis (Henoch-Scholein) urticarial vasculitis acute haemorrhagic oedema of infancy erythema elevatum diutinum
what are the types of cryoglobulinemia?
type II and III
what are some conditions where small and medium vessels are affected?
cryoglobulinemia ANCA-associated vasculitis
what are the types of ANCA-associated vasculitis?
EGPA (Churg-Strauss) microscopic polyangiitis GPA (Wegener)
what is a condition that affects medium vessels?
polyarteritis nodosa (PAN)
what are the 2 types of polyarteritis nodosa (PAN)?
benign cutaneous form systemic form
what are some examples of large vessel conditions?
temporal arteritis tayakasu
how does small vessel vasculitis usually manifest?
purpura (macular/palpable)
how does medium vessel vasculitis usually manifest?
digital necrosis retiform purpura ulcers subcutaneous nodules along vessels
what are the signs and symptoms of granulomatosis with polyangitis (ANCA-associated vasculitis)?
cough, dyspnoea, and chest pain pulmonary infiltrates glomerulonephritis
what are the small vessel manifestations of granulomatosis with polyangitis (ANCA-associated vasculitis)?
purpura (macular/flat or popular /palpable)
what are the medium vessel manifestations of granulomatosis with polyangitis (ANCA-associated vasculitis)?
retiform purpura digital necrosis livedo reticularis subcutaneous nodules distributed along blood vessels ulcers
what is sarcoidosis?
systemic granulomatous disorder affects multiple organs (commonly lungs)
what are some clinical manifestations of sarcoidosis?
(extremely variable) cutaneous manifestations in 1/3 - red-brown to violet pupules on face, lips, upper back, neck, extremities grainy, rough plaques lupus pernio (facial manifestation) ulcerative scar sarcoid erythema nodosum (inflammation of subcutaneous fat in legs) hypopigmentation
what does histology show in sarcoidosis?
non-caseating epithelioid granulomas
what possibility needs to be excluded in sarcoidosis?
possibility of infection - tissue biopsy for culture or PCR needed
how is underlying lung involvement evaluated in sarcoidosis?
chest x-ray further diagnostics if needed - pulmonary function tests - high resolution CT thorax
what is drug reaction with eosinophilia and systemic symptoms (DRESS)?
multi systemic drug reaction causes skin, solid organ and haematological disturbances
what are the most common features of drug reaction with eosinophilia and systemic symptoms (DRESS)?
rash - characteristic rash e.g. facial oedema - widespread rash (e.g. erythroderma) fever ≥ 38.5°C lymphadenopathy peripheral eosinophilia >0.7 × 109 internal organ involvement (liver, kidneys, cardiac)
how can internal organ involvement in drug reaction with eosinophilia and systemic symptoms (DRESS)?
liver (hepatitis) - most frequent cause of death kidneys (interstitial nephritis) heart (myocarditis) brain (altered consciousness/cognition) thyroid (thyroiditis) lungs (interstitial pneumonitis)
how is drug reaction with eosinophilia and systemic symptoms (DRESS) diagnosed?
(clinical examinations including serology, scoring criteria) fever lymphadenopathy ⩾ 2 sites, > 1cm circulating atypical lymphocytes peripheral hypereosinophilia internal organs involved negative ANA, hepatitis / mycoplasma, chlamydia skin involvement - >50% BSA - cutaneous eruption suggestive of DRESS e.g. facial oedema - biopsy suggestive of DRESS
what is the underlying mechanism for drug reaction with eosinophilia and systemic symptoms (DRESS)?
not known
what triggers drug reaction with eosinophilia and systemic symptoms (DRESS) onset?
2-6 weeks after drug exposure
what are the most common symptoms of drug reaction with eosinophilia and systemic symptoms (DRESS)?
fever and rash
what are some drugs that may cause drug reaction with eosinophilia and systemic symptoms (DRESS)?
antiepileptics sulfonamides antibiotics minocycline ibuprofen (NSAIDs)
how does drug reaction with eosinophilia and systemic symptoms (DRESS) progress?
initial sites of involvement - face, upper trunk, extremities spreads downwards and inward
what are the 5 types of rash morphology in drug reaction with eosinophilia and systemic symptoms (DRESS) progress?
urticated papular exanthem - widespread papules, raised morbilliform eruption erythroderma/widespread exfoliative erythema head/neck oedema erythema multiform-like
how is drug reaction with eosinophilia and systemic symptoms (DRESS) treated?
withdrawal of culprit drug corticosteroids to suppress inflammatory response (1st line, may require months of treatment)
what is Schnitzler syndrome?
late‐onset acquired autoinflammatory syndrome
when does urticaria manifest?
as an allergy manifestation of vasculitis chronic autoimmune disease related to lupus related to autoinflammatory syndromes due to underlying infection
what is usually the first sign of Schnitzler syndrome?
recurrent urticarial rash non‐pruritic urticated macules, papules or plaques particularly on trunk resolve with brownish hyperpigmentation
how does Schnitzler syndrome manifest?
recurrent fever above 40°C muscle, bone, joint pain (especially over ilium or tibia)
what symptoms are present in Schnitzler syndrome after diagnostics?
raised monoclonal IgM lymphadenopathy, hepatomegaly or splenomegaly neutrophilia elevated acute phase reactants or abnormal bone imaging
how is mild Schnitzler syndrome treated?
colchicine
how is severe Schnitzler syndrome treated?
anakinra
what is graft versus host disease?
multiple organ disease (acute/chronic) occurs in 10-80% of allogenic haematopoietic stem cell transplants
what are the typical features of graft versus host disease?
extensive rash of face, trunk and limbs – erythematous macules and papules with large areas of confluence ~60% BSA scleral icterus oral ulceration
what 3 things indicate that a rash is more likely to be graft versus host disease than a drug?
face involvement acral involvement diarrhoea
what is the pathogenesis of graft versus host disease?
donor-derived T-lymphocyte activity against antigens in an immunocompromised recipient
what organs does graft versus host disease usually affect?
skin liver GI tract
what is pruritis?
itching without rash suggestive of internal cause
what are the 2 haematological causes of pruritis?
lymphoma (may cause night sweats, weight loss, fever) polycythemia
what are the non-haematological causes of pruritis?
uraemia (renal failure) cholestasis iron deficiency or iron overload HIV / hepatitis A, B, C cancer drugs (e.g. opiates/opioids) psychogenic pruritus of old age (connections between keratinocytes is more frayed)
what investigations are done for pruritis?
FBC, LDH renal profile liver function tests ferritin chest x-ray HIV/hepatitis A, B, C
why are FBC and LDH tested in pruritis?
check haematological causes
why is a liver function test done in pruritis?
check cholestasis
why is ferritin tested in pruritis?
iron deficiency/overload
why is a chest x-ray done for pruritis?
general screen for lymphadenopathy, intrathoracic masses
what can pruritis cause?
nodular prurigo
what is systemic amyloidosis?
manifestation of underlying plasma cell dyscrasia
what is the composition of amyloid?
fibrils composed of AL protein (immunoglobulin light chains, usually λ chains)
what are some symptoms that may present in systemic amyloidosis?
weight loss fatigue paraesthesia dyspnoea syncopal attacks (orthostatic hypotension) (varied presentation)
what investigations should be done for systemic amyloidosis?
abdominal fat/rectal mucosa biopsy serum amyloid protein scintigraphy
how is systemic amyloidosis treated?
melphalan autologous peripheral blood stem cell transplant lenalidomide bortezomib
why are petechiae, purpura and ecchymoses present in systemic amyloidosis?
infiltration of vessel walls
what are the cutaneous features of systemic amyloidosis?
periorbital purpura (‘raccoon sign’) waxy, translucent or purpuric papules, nodules found on face, neck, scalp, anogenital region, digits
what can precipitate periorbital purpura in systemic amyloidosis?
coughing Valsalva manoeuvre pinching (pinch purpura)
what is scurvy?
vitamin C deficiency
what are the features of scurvy?
spongy gingivae with bleeding and erosion petechiae, ecchymoses, follicular hyperkeratosis corkscrew hairs with perifollicular haemorrhage
what are petechiae?
pinprick bruising
what is ecchymosis?
bruising