Back to
Updated on May 28, 2024
Indolent systemic mastocytosis (ISM) is the most common form of systemic mastocytosis, a group of disorders that cause an overgrowth of mast cells.
Mast cells are a type of white blood cell that play an essential role in inflammation, which helps protect the body from infections and injuries. With systemic mastocytosis, a genetic mutation causes mast cells to produce at a much faster rate than normal.
This creates a buildup of excess mast cells in tissues and organs, such as the skin, bone marrow, and small intestine. Having too many mast cells creates an outsized inflammatory response, which can damage surrounding tissues and organs. It can also cause a life-threatening allergic reaction called anaphylaxis.
ISM is the least severe type of systemic mastocytosis. Generally, people with ISM have a normal life expectancy and do not experience the organ damage seen with more advanced forms of systemic mastocytosis.
Still, people living with ISM do experience uncomfortable symptoms that can disrupt everyday life. They must also cope with the stress of having a chronic health condition that requires ongoing management, and the knowledge that ISM can cause anaphylaxis.
Patient education and support are an important part in managing ISM. The following resources can help you get started.
The Mast Cell Disease Society
The Mast Cell Disease Society is a patient advocacy organization dedicated to supporting people whose lives have been affected by mast cell diseases and furthering medical research about mast cell diseases. This includes systemic mastocytosis as well as other conditions that involve mast cells. The website’s section on systemic mastocytosis features an excellent overview of ISM, including an explanation of the genetic mutations associated with ISM. The website also has a printable template for emergency care protocols in case of anaphylaxis, which can be useful to both people with ISM and their healthcare providers. There is also a page on support groups and online forums, for anyone who wants to connect with other people who are living with mast cell disease.
National Organization for Rare Disorders (NORD)
ISM and other forms of systemic mastocytosis are rare disorders, and when researching any rare disorder, the National Organization for Rare Disorders (NORD) is a good place to start. The NORD website features background information on ISM and where it fits among other forms of systemic mastocytosis. It also features the RareCare Patient Assistance Programs, which provide assistance for patient education, financial assistance, and caregiver aid. Information on eligibility and how to apply to these programs is available through NORD’s website.
Genetic and Rare Diseases Information Center
Part of the National Institutes of Health (NIH), the Genetic and Rare Diseases Information Center, or GARD, is a good site for background information on mastocytosis. Though the site does not focus specifically on ISM, it does offer a helpful breakdown of systemic mastocytosis symptoms, a page on finding a physician, and information on where to find support for people and caregivers affected by any form of mastocytosis.
NCI Dictionary of Cancer Terms
Although ISM is not a form of cancer, The NCI Dictionary of Cancer Terms is a useful site to bookmark for those times when you come across a new term or phrase and want to quickly look up a definition. The dictionary features terms and definitions related to a wide variety of health conditions beyond cancer. Definitions also include audio readings and phonetic spellings.
