Dermatologic Manifestations of Granulomatosis with Polyangiitis (GPA) Skin involvement in granulomatosis with polyangiitis (GPA) is common and can appear as an initial presentation of the disease or more commonly through its course. GPA causes disease via: • Necrotizing granulomatous inflammation • Pauci-immune vasculitis Skin lesions: • Rarely dominate the clinical picture • Usually parallel the disease process Where? • Typically located on the lower extremities, but they can also manifest on the face, upper extremities, and the extensor surfaces of the joints • Oral and nasal ulcerations may also occur Skin Findings: • Petechiae, Palpable purpura (16%) • Painful skin lesions (9.4%) • Maculopapular rash (6.7%) • Hemorrhagic Bullae/Blisters • Ulceration (which may resemble pyoderma gangrenosum) • Urticaria • Papulo-necrotic lesions • Dermal/subcutaneous nodules • Livedo reticularis • Necrotic lesions and gangrene Skin lesions associated with pruritus, burning sensation or pain: • Petechiae • Palpable purpura • Vesicles overlying purpuric macules • Erythematous nodules • Ulcerated, erythematous nodules • Livedo reticularis Differential Diagnosis: Vasculitis: • Polyarteritis nodosa • Microscopic polyangiitis • EGPA • Henoch-Schönlein purpura • Mixed cryoglobulinemia • Goodpasture syndrome • Giant cell arteritis Infections include the following: • Mycobacterial diseases • Fungal infections (histoplasmosis, blastomycosis, coccidioidomycosis) • Streptococcal pneumonia with glomerulonephritis Malignancies include the following: • Nasopharyngeal carcinoma • Hodgkin disease • Non-Hodgkin lymphoma • Angiocentric lymphoma (lymphomatoid granulomatosis) • Castleman disease Skin Biopsy - Can Demonstrate: • Granulomatous vasculitis (inflamed blood vessels with a certain pattern of inflammation) • Necrotising vasculitis, extravascular palisading granulomas, and leukocytoclastic vasculitis #Dermatologic #Granulomatosis #Polyangiitis #GPA #dermatology #rash #diagnosis #rheumatology
