Purpura - Differential Diagnosis Framework Non-blanchable, dark red to purple, hemorrhagic skin lesions that result from leakage of RBC's secondary to platelet disorders, vascular disorders, coagulation disorders, or other causes. Etiology: • Vascular occlusion • Disruptions in vascular integrity/inflammation • Thrombocytopenia • Platelet defects • Coagulation disorders CAUSES OF NON-PALPABLE PURPURA: Platelet Defects/Quantity: • Primary Causes: - Thrombocytopenia: ITP • Secondary Causes: - Drug induced - Bone marrow disease - DIC/TTP/HUS - Hemolytic anemia - Splenomegaly - CTD (SLE) - Viral infections - Hemangiomas: - Kasabach-Merritt syndrome Coagulation Defects: • DIC, TTP/HUS • Anticoagulants (Warfarin necrosis) • VIT K deficiency • Liver disease • Hemophilia • Von Willebrand disease (VWD) • Hypercoagulable States: - Livedo reticularis - Retiform purpura - Protein C/S deficiencies - PNH - APLS • Acute Infectious Purpura Fulminans (DIC Features Present): - Neisseria meningitidis - Varicella - Group A Streptococcus - Streptococcus pneumoniae Vascular Fragility: • Decreased Support Of Dermal Vessels: - Amyloidosis - Corticosteroids - Vitamin C/Scurvy - Actinic damage - Solar purpura - Trauma • Collagen Disorders: Ehlers-Danlos • Pigmented Purpuric Dermatosis: Schamberg Disease Others: • Fat emboli • Cholesterol emboli • Septic emboli • Gardner-Diamond syndrome CAUSES OF PALPABLE PURPURA: Vasculitis: • Hypersensitivity/Leukocytoclastic vasculitis • Ig A vasculitis/HSP • Cryoglobulinemia (MIXED) • ANCA associated small vessel vasculitis - GPA - EGPA - MPA • CTD Associated - SLE, Sjogren's. • HCV, HBV Not Vasculitis: • Meningiococcemia • Gonococcemia • Rocky mountain spotted fever • Drug reactions • Erythema gangrenosum • Bacterial endocarditis • Liveoid Vasculopathy #Purpura #Differential #Diagnosis #hematology #rheumatology #palpable #nonpalpable #dermatology
