How do I hand the accusations of abuse?

My 3yo son has a bleeding disorder called vonWillebrand disease. It was inherited from me. While his little brother has it as well, my 3yo has a much more severe form. I am constantly bombarded with accusations of abuse because he is covered in bruises. (If you don't know what vonWillebrand disease is, read up on it). His stepfather is a hemophiliac, and I have talked to her about how she raised two hemophiliacs and the accusations, dirty looks, and snide remarks she got. Is there anything I can do?