Causes of Petechial Rash - Differential Diagnosis Algorithm Pinpoint areas (less than 2 mm) of hemorrhage, which are reddish-purple lesions called petechiae. Petechiae Etiology: • Abnormalities in primary or secondary hemostasis: - Thrombocytopenia - Abnormal platelet function - Clotting factor deficiency - Abnormal clotting factor function • Disruptions in vascular integrity: - Trauma - Infection - Vasculitis - Collagen disorders Petechiae Red Flags: • Fever • Toxic appearance • Hypotension • Mucosal lesions • Severe pain • Extremes of age • Immunosuppressed • New medication Febrile, Toxic Patient: • Palpable Rash: - Meningococcemia - Disseminated gonococcal infection - RMSF - Henoch Schonlein Purpura - Endocarditis • Non-Palpable Rash: - Purpura fulminans - DIC - TTP Afebrile, Nontoxic Patient: • Palpable Rash: - Autoimmune Vasculitis (lupus, RA, Sjogren's, GPA, EGPA, Microscopic) - Viral (echovirus, coxsackie, measles, Parvovirus) • Non-Palpable Rash: - ITP - APLS - HIT - ITP - Cholesterol embolism - Amyloidosis - Nutritional deficiency Work Up: • Complete blood count coagulation studies • Urinalysis • Fecal occult blood test • Serology for hepatitis B and C • Serum protein electrophoresis, anti-streptolysin O titre • Measurement of antinuclear antibodies, antineutrophil cytoplasmic antibodies, rheumatoid factor • Serum immunoglobulins & cryoglobulins • Skin biopsy • Abdominal ultrasound #Petechial #Petechiae #Rash #Differential #Diagnosis #Algorithm #Causes #dermatology #physicalexam
