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Systemic mastocytosis

Other Names for this Disease
  • Agressive systemic mastocytosis
  • Indolent systemic mastocytosis
  • Mast cell leukemia
  • SMCD
  • Systemic mast cell disease
More Names
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What is systemic mastocytosis?

How is systemic mastocytosis diagnosed?

How might systemic mastocytosis be treated?

What is systemic mastocytosis?

Systemic mastocytosis is a condition caused by the accumulation of mast cells in more than one part of the body. Mast cells contain substances such as histamine that regulate allergic reactions. In systemic mastocytosis, mast cells may build up in the bone marrow, internal organs, or in the skin. This condition is usually diagnosed in adults. Treatment is generally based on a person's symptoms, but it may include antihistamines (to prevent the effect of mast cell histamine) or chemotherapy for more aggressive forms.[1]

There are several different types of systemic mastocytosis. Indolent systemic mastocytosis develops slowly, while aggressive systemic mastocytosis develops more rapidly. Another form, called systemic mastocytosis with associated hemotologic non-mast cell lineage disease (SM-AHNMD), is characterized by the presence of several types of blood disorders. Mast cell leukemia is a rare form of systemic mastocytosis.[2]
Last updated: 10/5/2012

How is systemic mastocytosis diagnosed?

The diagnosis of systemic mastocytosis may be based on a number of different types of studies including skin and bone marrow biopsies; measurement of mast cell mediators in blood and urine; blood count; liver function studies; imaging studies; and genetic tests.[3]

A bone marrow biopsy is the most useful test used to diagnose the condition, and skin biopsy may be necessary for those with skin manifestations. Blood tests may show anemia, elevated histamine levels, thrombocytopenia, high white blood cell count (leukocytosis), low blood albumin levels (hypoalbuminemia), high serum tryptase levels, and/or other findings. Imaging studies may help to identify the extent and stage of the disease. Individuals with abdominal pain may need GI radiography, ultrasonography, or a liver-spleen computed tomography (CT) scan. Skeletal surveys and bone CT scanning may be necessary for those with suspected bone involvement. Genetic studies indicate that about 20% of patients with systemic mastocytosis have an abnormal karyotype (picture of an individual's chromosomes), and molecular genetic testing for a specific gene change (mutation) is typically positive.[4]

Because systemic mastocytosis may present in a wide variety of ways with a range of signs and symptoms, individuals who have specific questions about when to be tested and which tests are most appropriate for them should speak with their health care provider.
More detailed information about the studies used to diagnose systemic mastocytosis, as well as the diagnostic criteria, are available on eMedicine's Web site and can be viewed by clicking here.
Last updated: 2/1/2012

How might systemic mastocytosis be treated?

Treatment for systemic mastocytosis is based on each individual's symptoms. This includes efforts to control anaphylaxis and other allergic reactions, itching (pruritus) and flushing, and intestinal malabsorption.[5]  Some of the  medications used to treat systemic mastocytosis include:[6]

  • Antihistamines to treat itching, other skin complaints, severe flushing and low blood pressure before symptoms appear, and ulcers;
  • Proton pump inhibitors to relieve ulcer-like symptoms;
  • Epinephrine to treat symptom flares which occur with shock, referred to as anaphylaxis;
  • Steroids to treat malabsorption (impaired ability to take in nutrients); and  
  • Cromolyn sodium which may help reduce cramping in the abdomen.

In cases in which mastocytosis is malignant, cancerous, or associated with a blood disorder, steroids and/or chemotherapy may be necessary.[6]

More specific information about treatment options can be accessed through the Treatment and Medication sections of the Medscape Reference web site.

Last updated: 10/5/2012

  1. Mastocytosis. National Institute of Allergy and Infectious Diseases. January 2011; Accessed 5/15/2013.
  2. All About Mastocytosis. The Mastocytosis Society, Inc. 2011; Accessed 10/5/2012.
  3. Systemic Mastocytosis. American Academy of Allergy Asthma and Immunology. 2012; Accessed 1/30/2012.
  4. Koyamangalath Krishnan. Mastocytosis, Systemic. eMedicine. July 29, 2010; Accessed 2/1/2012.
  5. Krishnan K, Jaishankar D. Systemic Mastocytosis Treatment & Management. Medscape Reference. February 2012; Accessed 10/5/2012.
  6. Mastocytosis: Treatment. National Institute of Allergy and Infectious Diseases (NIAID). January 2011; Accessed 10/5/2012.