Vasculitis

Vasculitis describes inflammation of blood vessels—the network of tubes that carry blood throughout the body. When vessel walls become inflamed, they can leak fluid, weaken, or narrow, affecting the tissues those vessels supply. The condition can involve vessels of any size, from the smallest capillaries in the skin to larger vessels deeper in the body, and the signs often reflect which vessels are affected. Owners most commonly notice skin changes: patches of redness, bruising, ulcers, or crusting, particularly on the ears, paws, tail tip, or other areas where skin is thinner or more exposed. Some animals develop swelling in the legs, or small raised spots that may feel firm or tender. In other cases, the first signs are less visible—lethargy, joint discomfort, or changes in appetite—because vessels in internal organs or tissues are involved. The pattern and severity vary widely, and the same outward signs can arise from many different underlying causes. This page explores what signals may point toward vasculitis, what processes can trigger inflammation in vessel walls, how the condition is investigated through examination and testing, and what approaches exist for managing it. The goal is to help you understand what vasculitis means in veterinary medicine and what shape the conversation with your vet may take.