Purpura and microvascular occlusion Flashcards
When does warfarin necrosis usually occur?
3-5 days post commencing warfarin
5 types of PPD
Shamberg’s disease
Itching purpura (eczematid like purpura of doucas and kapetanakis)
Pigmented purpuric lichenoid dermatoses of Gougerot and Blum
Lichen aureus
Pupura annularis telangiectoides (Majocchi’s)
Atrophie blanche associated with
Associated with chronic venous hypertension and varicosities but this form does not have surrounding livedo reticularis, also seen in Antiphospholipid ab related syndromes, sickle cell ulcers.
2 classic triads of cholesterol embolic
1: leg/foot pain + livedo reticularis + preservation of good peripheral pulses
2: livedo reticularis, renal insufficiency and eosinophilia.
Achenbach’s syndrome (paroxysmal finger haematoma)
Recurrent painful bruising on palms & palmar aspects of fingers, likely venous rupture.
What to exclude if you suspect PPD
MF
Drug causes
Infections eg beta haemolytic strep
Who gets ppd of gougerot and Blum?
Men between 40-60.
Degos disease aka
Malignant atrophic papulosis
Classification of purpura
1) petechiae
2) macular erythema
3) ecchymoses
4) palpable pupura
5) inflammatory retiform
6) non inflammatory retiform
Histology of PPD
perivascular infiltrate of lymphocytes and macrophages is centered on the superficial small blood vessels of the skin. Signs of endothelial cell swelling and narrowing of lumina may be seen. RBC extravasation and haemosiderin. Perl’s to confirm haemosiderin and Fontana-Masson to exclude melanin
tx of Sneddons
No effective treatment.
Avoid smoking, OCP
Treat HTN, hyperlipidaemia
Antiplatelets in longer term, thrombolytic and vasodilators
If antiphospholipid abs or lupus anticoagulants: warfarin.
Important hx factors in retiform pupura
Sx of infection, exacerbation in cold
Hx of thrombotic disease, renal disease, haematological disease, CV disease, connective tissue disease
Fam hx of thrombotic disease
Drug hx eg warfarin, levamisole in cocaine.
Miscarriage hx
Red flags for purpura
- Larger or variably sized esp when no in sun damaged skin
- Numerous or widespread lesions
- Lesions occurring in crops
- Palpable lesions
- reticulate
- Associated features eg pustules, necrosis, nodules, splinter haemorrhages
- Evidence of bleeding from other sites eg haematuria
- Associated general sx
Investigation of suspected occlusive syndromes
FBC, coags, elfts, ancas, biopsy
Causes of retiform pupura
Non-inflammatory: microvascular occlusion, protein C and S deficiency, cholesterol emboli
Inflammatory occlusion:
-IgA vasculitis
-mixed cryo, rheumatic, PAN, microscopic polyangiitis, wegeners, churg-strauss), livedoid vasculopathy, septic vasculitis, pernio, PG.
-Calciphylaxis, heparin or warfarin necrosis, antiphospholipid ab syndrome
