Differential diagnosis of vasculitis

Lead authors

Luca Moroni, MD, MSc

Unit of Immunology, Rheumatology, Allergy and Rare Diseases, IRCCS San Raffaele Hospital, Milan, Italy

Giovanni Costanzo, MD

Personalized Medicine, Asthma and Allergy, IRCCS Humanitas Research Hospital, Rozzano, Italy

Editor-in-Chief

Mine Durusu-Tanriover, M.D. Prof.,

Department of Internal Medicine, Division of Internal Diseases, Hacettepe University Faculty of Medicine, Ankara, Turkiye

About this e-learning module

This interactive e-learning module systematically reviews the definition, classification, and clinical heterogeneity of vasculitis by examining small-, medium-, and large-vessel disorders. It highlights the essential role of clinical evaluation, imaging techniques, laboratory markers, and tissue biopsy in confirming the diagnosis. In addition, the module emphasizes the importance of ruling out mimickers such as infections, malignancies, connective tissue diseases, and drug-induced syndromes. A real-life case example illustrates how a combination of organ-specific evaluations, diagnostic imaging, and biopsy findings can confirm or exclude vasculitis. Ultimately, this module highlights the need for a meticulous, multidisciplinary approach to achieve accurate classification and identification of vasculitis. This e-learning module contains 14 pre-assessment questions and 14 post-assessment questions, all of which are multiple-choice.

This e-learning module was developed by: EFIM Academy

Learning points

By the end of this module, the learners will be able to

• recognize the clinical spectrum and classification of vasculitis based on vessel size and underlying pathogenesis
• be able to identify key diagnostic tools—including laboratory tests, imaging modalities, and histopathology—that aid in differentiating vasculitis from its mimickers
• be acquainted with a multidisciplinary approach to evaluate organ involvement and rule out secondary causes in patients with suspected vasculitis

Take-home messages

• The clinical spectrum of vasculitis is heterogeneous, but a careful study of organ involvement can help distinguish vasculitis based on the size of the affected vessel
• For each suspected type of vasculitis, it is vital to rule out the most common mimickers, particularly infections and tumors
• Certain conditions, such as infections (especially viral ones), tumors, and substance abuse, can both imitate vasculitis and cause it
• Some demographic, clinical and instrumental elements can help diagnose vasculitis, but the most specific tests are antibodies and, foremost, biopsy
• The diagnosis of vasculitis is complex and requires a multidisciplinary approach, along with a thorough evaluation to assess organ involvement and differentiate between subtypes and mimickers

Target Audience

This e-learning module is suitable for medical students and trainees and specialists working in Internal or Emergency Medicine services.

Additional information

• This e-learning module is designed to last approximately 60 minutes in total.
• All authors and the e-learning module editors have declared that they have no conflicts of interest in relation to the material in this e-learning module.
• The production of this e-learning module was funded entirely by the EFIM Academy. No external sponsorship was received.
• The material used in this e-learning module was prepared in 2025.
• Unless otherwise stated, all display items are provided courtesy of the e-learning module authors.
• Learners are invited to test their knowledge at the beginning and the end of the e-learning module via 14 questions.
• The e-learning module has a pass mark of 70%. Those scoring less than the required pass mark are encouraged to revisit the e-learning module and retake the assessment.

Released on 27 January 2026

CME Accreditation

“The Differential Diagnosis of Vasculitis” made available on https://www.efimacademy.org and organized by European Federation of Internal Medicine is accredited by the European Accreditation Council for Continuing Medical Education (EACCME®) to provide the following CME activity for medical specialists.

Only those e-learning materials that are displayed on the UEMS-EACCME® website have formally been accredited.

Through an agreement between the Union Européenne des Médecins Spécialistes and the American Medical Association, physicians may convert EACCME® credits to an equivalent number of AMA PRA Category 1 CreditsTM. Information on the process to convert EACCME® credit to AMA credit can be found at https://edhub.ama-assn.org/pages/applications.

Information regarding the conversion of EACCME® credits

Credit will be converted based on one (1) hour of participation equalling one credit for all activities. Physicians wishing to convert EACCME® credits to AMA PRA Category 1 Credit™ will be required to access the AMA website at https://edhub.amaassn.org/pages/applications to obtain the necessary paperwork and instructions. Physicians and other health care professionals will be required to pay a processing fee to the AMA.

For other countries, please contact the relevant national/regional accreditation authority.