Over the last decade, there have been significant advances in the understanding of the pathogenesis of vasculitis and the emergence of new therapeutic regimens for vasculitis. What used to be fatal diseases have now become chronic, treatable diseases. While overall outcomes have improved, some of the vasculitides may still be life threatening. The same medications which have markedly improved survival may also lead to serious complications such as infections, malignancy and infertility. In addition, accelerated atherosclerosis and thrombo-embolic disease have emerged as factors significantly impacting morbidity and mortality in vasculitis patients. Novel targeted therapies are under investigation and their success or failure may hinge upon the use of correctly classified patient populations and meaningful outcome measures. This volume of Best Practice & Research Clinical Rheumatology consists of articles written by experts on vasculitis who discuss the current status and future directions of topics including classification criteria, outcome measures, co-morbidities, fertility and pregnancy, advances in imaging techniques and management in the intensive care unit.

Since the vasculitides are a diverse group of diseases with frequent overlapping manifestations, it is important to have criteria for each syndrome. Diagnostic criteria do not yet exist and existing classification criteria are in need of a revision. Dr. Waller and colleagues trace the evolution of classification criteria for vasculitis and discuss the benefits and limitations of the widely used American College of Rheumatology (ACR) criteria, the classification criteria for childhood vasculitis and the 2012 revised Chapel Hill Consensus Conference on nomenclature of vasculitis. An international collaborative effort is underway to address the need for diagnostic and classification criteria.

Outcome measures are needed that not only are sensitive to change but also measure meaningful change for the patient. Dr. Tomasson discusses how health-related quality of life is affected by vasculitis, describes currently available outcome measures and highlights the need for development of patient-reported outcome measures as well as composite measures incorporating physician measures, patient-reported outcomes and serologic markers.

The use of non-invasive imaging techniques in the diagnosis and follow-up of vasculitis is increasing. Doppler ultrasonography, computed tomography/angiography, magnetic resonance imaging/angiography and positron emission tomography provide important information regarding the presence of inflammation and/or structural changes in the vasculature. Professor Schmidt discusses how different imaging techniques aid in the diagnosis of vasculitis, allow delineation of the extent of organ involvement and aid in monitoring response to therapy. It is possible that in certain circumstances with typical clinical manifestations, imaging studies may soon replace histological studies because of highly specific findings. International multicentre studies addressing the role of imaging in vasculitis are currently in progress.

Although the increased risk of cardiovascular disease in patients with systemic lupus erythematosus and rheumatoid arthritis is well established, the impact of cardiovascular disease on the morbidity and mortality in vasculitis has only recently been recognised. Professor Cohen Tervaert reviews how vascular inflammation and damage, medications, myeloperoxidase and its oxidants, T-cells and autoantibodies play an important pathophysiological role in the acceleration of atherosclerosis in vasculitis beyond the traditional cardiovascular risk factors. Recommendations for treatment of accelerated atherosclerosis in systemic vasculitis are made.

While common in Behçet’s syndrome, emerging evidence suggests that thrombo-embolic disease may be more common than previously thought in vasculitides such as anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and giant cell arteritis. Dr. Gaffo provides a historical perspective on the relationship between thrombotic disease and vascular inflammation and reviews the clinical evidence for increased risk for thrombosis in certain vasculitides, especially during periods of active disease.

In the past, due to the fulminant nature of some vasculitides, preservation of fertility was not a priority. Now that outcomes have improved, issues regarding fertility and pregnancy have emerged as important considerations when treatment is being initiated. Professor Pagnoux examines the impact of disease and cytotoxic medication on fertility and maternal and foetal outcomes. Gonad preservation and treatment options for fertility issues are discussed. Treatment options during pregnancy are also reviewed.

Certain vasculitides such as polyarteritis nodosa and cryoglobulinaemia are known to be associated with hepatitis B and C viruses. The search for other infectious agents as a cause for other forms of vasculitis is in progress and may be nearing fruition in giant cell arteritis. Professor Guillevin reviews current knowledge of infection-associated vasculitis. In addition, infections complicating vasculitis and the safety and efficacy of infection prophylaxis are discussed.

Impaired immunosurveillance and oncogenicity of immunosuppressive agents may increase the risk of malignancy in patients with vasculitis. Professor Mahr summarises the current understanding of the potential link between cancer and ANCA-associated vasculitis.

Vasculitis may be associated with life-threatening complications due to the underlying disease process or secondary infection. Drs. Wilfong and Seo review the diagnostic and therapeutic challenges of vasculitis patients admitted to the intensive care unit.

I am grateful to these vasculitis experts for providing their knowledge on the subjects they reviewed. I hope the readers enjoy and learn from these articles as I have and that some are motivated to investigate the topics raised in each article’s research agenda.