- Me and My Mast Cells - by Dr. Laurence Afrin, M.D. and author, contains information on diagnosis, treatment, drugs, MCAS doctors and a blog.
- The Low Histamine Chief - former news anchor with MCAS, Yasmina Ykelenstam, provides an informative blog, treatment and research information and yummy low histamine recipes and diet plans
- Positive Support - Facebook Site for Mast Cell Disorder, EDS, POTS and related illnesses
- Mast Attack - excellent information resource with guidance documents (I think I May Have Mast Cell Disease, Mast Cell Disease Fact Sheet) and blogs put together by 32 year researcher with MCAS ("She's a blast")
- The Mastocytosis Society - Resources, information packets, doctor references, advocacy - appears to be much more focused on mastocytosis than MSAC
- The Mast Cell Master - Research center for Dr. Theorharides, long-time mast cell researcher, and formulator of several nutrient combinations for MCAS
- Mast Cell Aware - information and resource site with latest news section