Is it Purpura, Petechiae or Ecchymoses?
Common etiologies of Palpable Purpura (histologically identified as leukocytoclastic vasculitis)
-Infections (eg: HIV, HBV, HCV, endocarditis among other viral infections)
–MEDICATIONS (many medications most commonly NSAIDS, cephalosporins, NSAIDS)
-Malignancies (eg: Paraneoplastic syndrome)
–Vasculitis (small vessel vasculitis)-see below.
When you think of palpable purpura with systemic symptoms, think about small vessel vasculitis. If NO systemic symptoms, think about cutaneous small vessel vasculitis (CSVV)
Types of Small vessel vasculitis (SVV)
-IgA vasculitis (HSP)
-ANCA associated Small Vessel Vasculitis (MPA, GPA, EGPA)
-NON-ANCA mediated (Infections, drug induced, CTD, Sjogrens, Goodpastures etc.)
How do you workup new onset vasculitis with palpable purpura?
-CBC, Chem 7, LFT, ESR, CRP
-Viral hepatitis panel + HIV
-Urinalysis for proteinuria or GA
-Blood cultures (rule out endocarditis)
-C3,C4 (low levels in cryoglobulinemia, SLE)
-CXR , CT (evaluate hemoptysis with DAH)
-Often skin biopsy is not necessary but can support diagnosis.
-Treat the underlying etiology, often requiring immunosuppression