Immunoglobulin A (IgA) vasculitis is small-vessel arteritis triggered by autoimmunity and allergies. IgA vasculitis among elderly patients is rare, and there is a lack of evidence regarding the choice of medicine and treatment duration. The main treatment for IgA vasculitis is steroids which can be cured with a small dose of prednisolone without immunosuppressants. Here, we report a case of a 90-year-old patient with the chief complaint of appetite loss and purpura on the legs who was diagnosed with IgA vasculitis based on biopsy results. The patient was initially treated with prednisolone effectively but exacerbated with steroid tapering, eventually requiring the use of an immunosuppressant. This case highlights the importance of monitoring the symptoms of IgA vasculitis while tapering steroids and clarifying the timing of immunosuppressant initiation.