- Several factors can trigger vasculitis in horses. Often, it is caused by an overreaction of the immune system, which attacks blood vessels in the skin. Possible triggers include:
- Infections (or problems following infections)
- Insect bites / parasites and allergic reactions
- Contact reactions (e.g. to chemicals, plants, personal care products)
- Sun/UV exposure (especially for sensitive, fair skin)
- Drug reactions (rare, but possible)
- Moisture, mud, friction as an amplifier (secondary problem)
Often it is not "one" trigger that is decisive, but the combination of trigger + skin stress + germ load.
To avoid confusing vasculitis with mud fever, mites, fungus, or contact dermatitis, the following are advisable, depending on the case:
- Clinical examination and course (sudden/chronic, bilateral/unilateral)
- Exclusion of parasites/fungi/bacteria (swab, skin scraping)
- Blood count/inflammatory markers in case of suspected systemic infection
- In unclear cases: skin biopsy
The diagnosis is important because the therapy depends on it.