Mast Cell Disorders: Mastocytosis and Mast Cell Activation Syndromes

Mast Cell Disorders: Mastocytosis and Mast Cell Activation Syndromes
Mast Cell Disorders: Mastocytosis and Mast Cell Activation Syndromes

ST. LOUIS, MO/March 28, 2017 (STL.News) Mast cells are found mainly in connective tissue, such as the lining of the airway, the skin, and the gastrointestinal track.  The cell’s main job is to release histamines when an individual is experiencing an allergic or inflammatory reaction, but they also play a critical role in keeping the body healthy.  Mast cells are a basophilic white blood cell that contains large cytoplasmic granules.  Mediators contained within the cells selectively release these granules depending on the reaction being experienced.  Mast cells that function properly can have many positive benefits to the individual, however some individuals suffer from mast cell disorders.  Mast cell disorders are caused from the over production of these cells, causing them to accumulate in tissues.  This can affect different parts of the body depending on where the accumulation occurs.  There are two major forms of mast cell disorders, Mastocytosis and mast cell activation syndromes (MCAS).

Mast cell activation Syndromes, or MCAS, is caused by the excessive releasing of chemical mediators at inappropriate times.  The result of which can be a multitude of symptoms including, but not limited to hives, gastrointestinal symptoms, low blood pressure, itching and headaches.  In order for an individual to be diagnosed with MCAS, they must exhibit chronic symptoms which involve at least two different organ systems which cannot be found to be caused by another condition of disorder.  The preferred method for diagnosis is an increase in the serum level of tryptase, an enzyme that is released as an allergic response.  Detection of surplus tryptase can be difficult to detect because the levels are often only raised for one to two hours after a systemic mast cell activation event.

Mastocytosis is the abnormal accumulation of mast cells, occurring in one or more organ systems.  Mastocytosis is separated into three broad categories: systemic mastocytosis, mast cell sarcoma, and cutaneous mastocytosis.  Cutaneous mastocytosis, or CM, is most commonly found in pediatric cases.  This form of Mastocytosis is often benign and results in the releasing of mediators by mast cells into the skin.  Fortunately, 67-80% of pediatric cases are resolved before adulthood.  CM is typically diagnosed through a biopsy of skin lesions caused by clusters of mast cells.  To obtain information on pediatric Mastocytosis please visit,  For donations or fundraising opportunities please contact Melissa Harbaugh, VP of Fundraising, at  All donations are tax deductible.

Unlike cutaneous mastocytosis, in which mast cells are visible on the skin, in systemic mastocytosis the cells accumulate internally.  The accumulations tend to focus in the spleen, bone marrow, liver, or small intestines.  The majority of SM cases are not inherited, but most likely caused by a mutation in the KIT gene.  There are four main categories of SM: Indolent systemic mastocytosis, systemic mastocytosis with an associated hematologic nonmast cell lineage, Aggressive systemic mastocytosis, and Mast cell leukemia.  The symptoms and treatment vary from one category to another as well as the area of the body the disorder has affected.  Mast cell sarcoma is aggressive and is often characterized by destructive growths of mast cells, such as found in a tumor.  For more information on any of these diseases or to donate to research please visit

Basic Pediatric Mastocytosis Information Sheet. (n.d.). Retrieved March 27, 2017, from

Jennings, S., PhD. (2017, January 16). Long-Awaited Advance in Drug Development! Midostaurin Shows Efficacy in Advanced Systemic Mastocytosis (Implications for Our Disease Community). Retrieved March 27, 2017, from

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Caley Johnson
About Caley Johnson 7 Articles
Caley Johnson holds a Bachelors degree from The University of Missouri - St. Louis in Elementary Education. Her areas of special study have been in English and Science. Caley has lived in St. Louis most of her life, with the exception of eight years during which she lived in Salida Colorado. Caley enjoys learning and working with students on a daily basis.