Mixed connective tissue disease (MCTD) is a rare connective tissue disorder combining clinical features of systemic lupus erythematosus (SLE), systemic sclerosis (SSc), polymyositis (PM) (see these terms) and/or rheumatoid arthritis (RA).

Purpura (from Latin: purpura, meaning \"purple\") is the appearance of red or purple discolorations on the skin that do not blanch on applying pressure. They are caused by bleeding underneath the skin. This term refers to an abnormally increased susceptibility to developing purpura. Purpura are larger than petechiae.