Various types of cutaneous lesions may occur in association with RA, including rheumatoid nodules (Figure), rheumatoid neutrophilic dermatitis, vasculitis, palpable purpura, and pyoderma gangrenosum. Many of these manifestations—including rheumatoid nodules—are specific for RA.3 The presence of these nodules is associated with seropositive disease and with a more severe, erosive clinical presentation. The nodules appear in 20% to 30% of patients with RA.4 Sites of predilection are those subject to shear stress, including the subcutaneous tissues over the extensor aspects of the elbow region, over the sacrum in bedridden persons, and at the pericardial and pleural surfaces.3
Histologically, the nodules show a central necrotic zone surrounded by macrophages and other cells in a palisading pattern. Rheumatoid-like lesions have also been reported in SLE.5 In one case, the nodules disappeared following treatment with hydroxychloroquine.5
Accelerated nodule formation develops in some persons treated with methotrexate.6 This noteworthy phenomenon occurs in patients with both seropositive and seronegative findings.