Erythrocyte sedimentation rate is commonly elevated in patients with Vilanova disease. Anti-streptolysin O titer should be checked, as it is elevated in some patients. The physician should also check a tuberculin skin test, since other diseases in the differential diagnosis can have tuberculous etiologies. A chest radiograph should be obtained to rule out sarcoidosis and tuberculosis. A complete blood count can be ordered to rule out infection, especially if the patient has described a sore throat or fever.
Skin biopsy is necessary to make the diagnosis.
A mild lymphocytic and giant cell inflammation is observed, often lining the walls of the septa. Eosinophils and neutrophils may also be observed. The endothelial cells of the small vessels proliferate and can fill the entire lumen. The capillaries can also take on a coiled, swollen appearance. There is little to no vasculitis or phlebitis.