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The Manual's Editorial Staff

Medically Reviewed Jan 2021 | Modified Sep 2022
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What is mastocytosis?

Mastocytosis is a buildup of mast cells in your skin and sometimes other parts of your body.

  • Mastocytosis is rare

  • Symptoms include itchy spots and bumps, flushing, an upset stomach, and sometimes bone pain

  • Mastocytosis can affect just your skin or other parts of your body, such as your lungs and lining of your intestines

  • Mastocytosis of the skin alone isn't life-threatening and sometimes goes away without treatment

  • Mastocytosis that affects other parts of your body is more serious and can even be life-threatening—you should carry a dose of epinephrine for emergency treatment

What causes mastocytosis?

Mastocytosis develops when your body makes too many mast cells. The mast cells can collect in your skin, bones, or other organs.

Mast cells produce a chemical called histamine. Too much histamine can cause:

  • Itching

  • Rash

  • Too much stomach acid

  • Low blood pressure

Doctors don’t always know why your body makes too many mast cells, but some people have a genetic mutation that causes mastocytosis.

What can trigger an attack of mastocytosis?

If you have mastocytosis, certain things can trigger an attack of symptoms, including:

  • Physical touch

  • Exercise

  • Things you eat or drink, such as foods, alcohol, and certain drugs

  • Insect stings

What are the symptoms of mastocytosis?

Symptoms include:

  • Small reddish brown spots or bumps that may itch

  • Flushing (turning red all over)

  • Stomach pain

  • Feeling sick to your stomach or throwing up

  • Diarrhea

  • Fainting and severe drops in blood pressure, which can be deadly

If mast cells build up in your tissues or organs, they can cause damage that can be life-threatening.

How do doctors tell if I have mastocytosis?

Doctors suspect mastocytosis from your symptoms, especially if you have itchy spots and get hives (red, itchy, raised patches on the skin) when you scratch. To know for sure, doctors will do tests, such as:

  • Biopsy (taking a small sample of skin to look at under a microscope)

  • Blood and urine tests

  • Sometimes, bone scan and genetic tests

How do doctors treat mastocytosis?

If you have mastocytosis only in your skin, doctors will treat itching and rashes with:

  • Antihistamines

  • Ultraviolet light

  • Corticosteroid creams

If mastocytosis affects other parts of your body, doctors will have you take medicine to help with your symptoms.

If your symptoms are severe, doctors may:

  • Give you a weekly shot to reduce the disease’s effects on your bones

  • Prescribe corticosteroids

  • Do surgery to remove your spleen, if mast cells have built up in your spleen

  • Have you carry an emergency dose of epinephrine (Epi-pen)

Drugs Mentioned In This Article

Generic Name Select Brand Names
Adrenaclick, Adrenalin, Auvi-Q, Epifrin, EpiPen, Epipen Jr , Primatene Mist, SYMJEPI, Twinject
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