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Purpuric / retiform
46/46
Petechiae (1-2 mm)
Macular purpura / ecchymosis
Palpable purpura
Retiform / stellate / livedo
Inflamed (halo, tender, indurated)
Bland (no surrounding inflammation)
Simple hemorrhage
Vasculitis
Microvascular occlusion
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NO FILTER · 46 CANDIDATES · DON'T-MISS ALWAYS SHOWN
COMMON (9)
Drug-induced thrombocytopenia
Heparin, quinine, vancomycin, linezolid, sulfonamides, valproate, GP IIb/IIIa inhibitors; review drug history
Platelet function defect (hereditary or acquired)
Normal platelet count with abnormal platelet function: Glanzmann thrombasthenia, Bernard-Soulier, storage pool disorders, aspirin and NSAIDs, P2Y12 inhibitors, uremia, liver disease, cardiopulmonary bypass
Valsalva-induced petechiae
Vomiting, coughing, lifting or childbirth; distribution above the clavicles, head and neck
Poor dermal support purpura
Bland purple-brown macular purpura with no pink halo and no induration, on dependent or trauma-prone areas; senile and solar purpura, corticosteroids, amyloid, anticoagulant excess
Viral infection with thrombocytopenia
HIV, CMV, EBV, parvovirus B19, dengue, hantavirus, COVID-19; fever, viral prodrome, travel history, mild-to-moderate thrombocytopenia, elevated CRP
Cutaneous small-vessel vasculitis
Idiopathic in 50%, otherwise triggered by drugs, infections or autoimmune disease; skin-limited by definition; early or resolving lesions may be only subtly palpable
IgA vasculitis (Henoch-Schonlein purpura)
Palpable purpura on the lower extremities plus arthralgias, abdominal pain and hematuria or IgA nephropathy; children > adults, usually post-URI; IgA on DIF; extensive disease may form reticulated patterns
Chilblains and pernio
Acral cold-induced inflammation, sometimes with a retiform pattern
Schamberg disease (progressive pigmentary purpura)
Asymptomatic patches with cayenne-pepper petechiae on a yellow-brown background, usually bilateral and symmetric on the lower legs; chronic; most common pigmented purpuric dermatosis
DON'T MISS (25) - ALWAYS SHOWN
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Immune thrombocytopenia (ITP)
Petechiae plus mucosal bleeding with hemostatically relevant thrombocytopenia (platelets <10-20 x 10^9/L); primary or secondary to SLE, HIV, HCV, lymphoma; check smear for clumping (pseudothrombocytopenia)
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Meningococcemia
Early petechiae before retiform progression in a febrile patient; blood cultures; empiric antibiotics should not wait for biopsy
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Rocky Mountain spotted fever
Unwell febrile patient with petechiae or intermediate purpura on the extremities and tick exposure; treat empirically while awaiting confirmation
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Infective endocarditis
Janeway lesions, Osler nodes and Roth spots; blood cultures and fundus exam; septic emboli
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Angioinvasive fungal infection (Mucorales, Aspergillus, Fusarium)
Immunosuppressed, neutropenic or diabetic host; tissue biopsy with PAS and GMS, fungal cultures
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Ecthyma gangrenosum
Pseudomonas or other gram-negatives in a neutropenic host; blood cultures and tissue biopsy
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Septic vasculitis
Bacterial or fungal vasculopathy with inflammation: disseminated gonococcemia, early meningococcemia, ecthyma gangrenosum; tissue cultures including atypical organisms in the immunosuppressed; empiric antibiotics should not wait for biopsy
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Thrombotic thrombocytopenic purpura
Microangiopathic hemolytic anemia with schistocytes on smear, neurologic findings and renal involvement; ADAMTS13 deficiency
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Hemolytic uremic syndrome
Microangiopathic hemolytic anemia on smear; STEC-HUS or complement-mediated (atypical) HUS
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Disseminated intravascular coagulation
Systemic coagulation defect with sepsis; thrombocytopenia with schistocytes, abnormal coags, low fibrinogen and elevated D-dimer
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Heparin-induced thrombocytopenia and thrombosis (HIT)
Paradoxical thrombosis with a drop in platelets 5-10 days into heparin; 4T score, anti-PF4 ELISA, serotonin release assay
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Purpura fulminans (protein C or S deficiency)
Neonatal onset, post-streptococcal or post-varicella, DIC with sepsis; homozygous neonatal or acquired postinfectious; protein C and S activity
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Warfarin-induced skin necrosis
Paradoxical thrombosis at warfarin initiation in protein C-deficient patients; breast, buttock and thigh; also vitamin K deficiency
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Antiphospholipid syndrome (including catastrophic APS)
Unexplained retiform purpura with livedo racemosa, SLE or atrophie blanche; lupus anticoagulant, anticardiolipin, beta-2 glycoprotein I; livedo racemosa plus stroke suggests Sneddon syndrome
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Mixed cryoglobulinemia (type II and III)
Often HCV-associated; purpura on the lower legs, weakness, arthralgias, peripheral neuropathy, glomerulonephritis; low C4 and positive rheumatoid factor
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Polyarteritis nodosa (cutaneous or systemic)
Tender subcutaneous nodules along arteries, livedo racemosa, ulcers and digital necrosis; hepatitis B-associated systemic PAN; cutaneous PAN limited to skin and peripheral nerves; biopsy must reach subcutis
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Granulomatosis with polyangiitis (GPA)
Upper and lower respiratory granulomas, glomerulonephritis, palpable purpura, ulcers, oral pyoderma gangrenosum-like lesions; c-ANCA/PR3
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Microscopic polyangiitis (MPA)
Glomerulonephritis, pulmonary capillaritis and palpable purpura, with less granuloma than GPA; p-ANCA/MPO
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Eosinophilic granulomatosis with polyangiitis (EGPA)
Asthma, eosinophilia, mononeuritis multiplex, palpable purpura and nodules; often p-ANCA/MPO
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Levamisole-adulterated cocaine vasculopathy
Retiform purpura on the cheeks and ears with agranulocytosis, MPO and PR3 ANCA, lupus anticoagulant; ask about cocaine use
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Pyoderma gangrenosum (atypical or bullous)
Inflammatory ulcers with violaceous undermined borders, sometimes purpuric early; pathergy; associated IBD, RA, hematologic malignancy, monoclonal gammopathy; biopsy excludes vasculitis, infection and malignancy rather than confirming PG
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Cryoglobulinemia type I
Acral distribution with a cold exposure trigger; monoclonal, from lymphoplasmacytic disorders; acral and ear involvement; cryocrit and immunofixation
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Cholesterol embolization syndrome
Sudden symmetric livedo after a recent arterial procedure or thrombolytic therapy, or >1-2 months of anticoagulation; acral cyanosis with intact pulses, peripheral eosinophilia, acute kidney injury
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Calciphylaxis (calcific uremic arteriolopathy)
Painful retiform purpura on adipose-rich areas in dialysis patients; CKD/ESRD with thrombophilia, warfarin or calcium-phosphate dysregulation; calcium-phosphate product, PTH, vitamin D
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Intravascular B-cell lymphoma
Fever, neurologic deficits, retiform purpura and elevated LDH; skin biopsy from the edge including deep dermis and subcutis, PET
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