Derm - Skin in Systemic Disease Flashcards
Why is learning about skin in systemic disease important?
→ rash may be more than skin deep
→ prevent or reduce internal organ damage by early diagnosis
What are the 4 ways in which the skin can be involved in systemic disease?
→ skin is targeted by disease
→ skin provides signs of internal disorders
→ tell-tale skin conditions
→ systemic disease can be secondary to the skin disorder
What is a punch biopsy?
→ skin investigation done under local anaesthetic
→ sent for histology for analysis, etc.
What is Lupus Erythematosus?
autoimmune disease in which the immune system attacks its own tissues, causing widespread inflammation and tissue damage in the affected organs
What are the 2 main types of LE? Is there an overlap between them?
→ systemic LE
→ cutaneous (discoid) LE
→ yes, there is some overlap
What is the mucocutaneous diagnostic criteria of LE?
→ cutaneous lupus (acute) (ring-like plaques) → cutaneous lupus (chronic) → oral ulcers → alopecia (baldness) → chilblains → photo distributed (sun-exposed) rash → livedo reticularis → palpable purpura
What is the systemic or internal diagnostic criteria of LE
→ synovitis (inflamed joints)
→ serositis (serous tissue inflammation) (pleurisy or pericarditis)
→ renal disorder
→ neurological disorder
What is the haematological diagnostic criteria for LE?
→ haemolytic anemia
→ thrombocytopenia
→ leukopenia
What are the immunological findings in LE?
main : auto-antibodies → ANA → anti-dsDNA → anti-Sm → antiphospholipid → low complement → Direct Coomb's test
What is the significant presenting differences between the 2 types of LE?
→ Cutaneous / Discoid LE has more evident scarring
→ Systemic LE has more ring like plaques, etc.
What is neonatal lupus?
autoimmune disorder that is congenital
What are the presenting signs of neonatal lupus in a newborn?
→ ring-like rash / plaques
→ likely to be positive for Ro antibodies
What test should immediately be done for newborns w neonatal lupus? Why?
→ ECG
→ 50% risk of heart block
→ might need a pacemaker
What is dermatomyositis?
→ autoimmune connective tissue disorder
→ proximal extensor inflammatory myopathy
What are the presenting signs of dermatomyositis?
→ Gottron’s papules (plaques on the metacarpal + phalanges)
→ ragged cuticles
→ Shawl Sign (redness of upper back)
→ Heliotrope rash (erythema of the eyelids)
→ photosensitive erythema
What are the different subtypes of dermatomyositis classified by?
clinical features the can be predicted by autoantibody profile
What DM subtype presents with fever, myositis + Gottron’s papules?
Anti Jo-1
What DM subtype presents with necrotising myopathy?
Anti-SRP
What DM subtype presents with mild muscle disease?
Anti Mi-2
What DM subtype is associated with malignancy in adults?
Anti-p155
What DM subtype is juvenile and usually presents with calcinosis?
Anti-p140
What DM subtype presents with amyopathia (lack of muscle weakness)?
Anti-SAE
What DM subtype presents with interstitial lung disease, digital ulcers, ischaemia?
Anti-MDA5
What diagnostic tests need to be done for dermatomyositis?
→ antinuclear antibody test → creatine kinase (looking for increased CK) → skin biopsy → EMG → LFT (looking for increased ALT) → screening for internal malignancy
What are the symptoms of IgA vasculitis?
→ abdominal pain → bleeding → Henoch-Schonlein purpura → arthralgia → arthritis → IgA associated glomerulonephritis
What type of vasculitis presents systemically in the skin?
→ cutaneous small vessel vasculitis
→ benign cutaneous form of Polyartertis Nodosa (medium vessel vasculitis)
What are the different causes of cutaneous small vessel vasculitis?
→ idiopathic → malignancy → LE → infectious → medication exposure → inflammatory → IgA vasculitis → Urticarial vasculitis → acute haemorrhagic oedema of infancy
How do the small vessel manifestations of vasculitis usually present on skin?
purpura (macular or palpable)
How do the medium vessel manifestations of vasculitis usually present in skin?
→ digital necrosis
→ retiform purpura ulcers
→ subcutaneous nodules along blood vessels
What is sarcoidosis?
systemic granulomatous disorder of unknown origin
can affect multiple organs
most commonly affects lungs
How many have cutaneous manifestations of sarcoidosis?
33%
How does sarcoidosis present cutaneously?
→ highly variable
→ red-brown to violaceous papules on the face, lips, upper back, neck + extremities
→ can look like lupus pernio (nothing to do with lupus)
→ ulcerative
→ scar sarcoid
→ erythema nodosum (on the legs)
What does histology show for sarcoidosis?
non-caseating epthelioid granulomas
What is DRESS?
→ Drug reaction with Eosinophilia + Systemic Symptoms
→ rash + systemic upset incorporating haematological + solid-organ disturbances
→ underlying mechanism unknown
What is the diagnostic criteria for DRESS?
based on scoring criteria:
→ fever > 38.5
→ lymphadenopathy > 2 sites + more than 1 cm
→ circulating atypical lymphocytes
→ peripheral hypereosinophilia > 0.7 x 10 to the power of 9
→ internal organs involved
→ negative ANA, hepatitis, mycoplasma, chlamydia
→ skin involvement >
What internal organs can be involved in DRESS ?
→ liver (hepatitis)(most frequent) → kidneys (interstitial nephritis) → heart (myocarditis) → brain → thyroid → lungs (interstitial pneumonitis)
What is the onset of DRESS?
2-6 weeks after drug exposure
What drugs can trigger DRESS?
→ sulfoamides → anti-epileptics → allopurinol → Antibiotics → minocycline → ibuprofen
What is the cutaneous manifestation of DRESS?
rash: → urticated papular exanthem, (widespread papules) → maculopapular eruption → widespread erythema → head / neck oedema → erythema multiform-like
What is the treatment for DRESS?
→ withdrawal of drug
→ corticosteroids are first line
What is Graft versus Host Disease?
→ multiple organ disease
→ affects 10% of allogenic haematopoetic stem cell transplants
How can you differentiate between GvHD and rash induced by a drug?
→ face involvement
→ acral involvement
→ diarrhoea
What is pathogenesis of GvHD?
donor-derived T-lymphocyte activity against antigens in an immunocompromised recipient
