Hi Grifmat,
Hope the doctor at Yale New Haven's Smilow Center will be able to make a diagnose! Perhaps your mother has ITP (Immune Thrombocytopenic Purpura) that not is a cancer but an autoimmune disease, These patients should not have platelet transfusions and are often treated with Prednisone or similar drugs.
You know it is not only the platelet count that is important - it is the quality of the platelets too. Your mother seems to have well functioning platelets since she has been as low as 7 without bleeding.
There are drugs that can improve platelets - for example Promacta - but they are not approved for MDS.
We can only try to avoid everything that can decrease platelets - look out for painkillers that often decrease platelets.
http://www.pdsa.org/about-itp/warnings.html
Tell your mother that bruising is not dangerous. I have had blood blisters in my mouth and small nose bleedings since diagnose 2006 when my dysfunctional platelets are low (22).
Kind regards
Birgitta-A
74 yo, dx MDS Interm-1 2006, supportive therapy until 2010. Since then positive effect from Thalidomide + Prednisone