There seems to be a distinction between petechiae that is a result of trauma of some sort (this is the better kind to have) and petechiae that is a result of inflamed veins or a reaction to inflammation (vasculitis).
"Vasculitis is an inflammation of the blood vessels. It is commonly associated with diseases such as SLE, scleroderma, ulcerative colitis, rheumatoid arthritis and dermatomyositis.
Immune complexes are formed when antigens bind to antibodies. If not excessive, and assuming a healthy immune response, these complexes are usually cleared from the circulation by the phagocytic system. These responses are usually delayed, occurring hours or even days after exposure to the antigen, from whatever source. When these complexes persist in the circulation, their interaction with platelets results in the release of vasoactive amines. Vasoactive amines cause increased vessel permeability, platelet aggregation (clotting) and initiation of the arachidonic acid cascade (inflammation). These immune complexes can also settle out within the postcapillary venules, with subsequent tissue inflammation, irritation and damage by complement activation, more inflammatory cells coming to the area and destructive lysosomal enzyme release."
"However, the truth in science ultimately emerges, although sometimes it takes a very long time," Arthur Silverstein, Autoimmunity: A History of the Early Struggle for Recognition