Mast Cell Diseases

What is mast cell disease?

Mast cell diseases are rare but increasingly recognized by doctors. People with mast cell disease experience unexplained flushing, abdominal pain and bloating, or severe reactions to foods, medicines or insect stings. They may feel hot, even in a normal-temperature room.

Symptoms could signal an allergic reaction, but if testing is inconclusive, your doctor may evaluate you for a mast cell disease.

Mast cell diseases (including mastocytosis, mast cell activation syndrome and hereditary alpha-tryptasemia) are caused by abnormal and/or overly active mast cells. Mast cells protect us from foreign invaders like germs and parasites. Everyone has mast cells and although they are helpful, they are also important culprits in allergic reactions and anaphylaxis.

Some people are born with the condition, while others develop it in childhood or adulthood.

People with mast cell diseases often struggle with severe symptoms and life-threatening reactions for years before finding a doctor with answers.

What are the symptoms of mast cell disease?

Mast cells release mediators, including histamine, tryptase, prostaglandins and leukotrienes, which can cause a host of symptoms. Some people with mast cell diseases may experience few symptoms intermittently. Others may have daily disabling symptoms affecting multiple organ systems. Symptoms may include:

• Skin: flushing, itching, rashes
• Gastrointestinal: Abdominal pain, bloating, nausea, diarrhea, vomiting, reflux (GERD)
• Neurological: Brain fog, cognitive problems, anxiety/depression, tremors, headaches
• Endocrine: weak bones, bone lesions, bone pain
• Cardiac: blood pressure changes with hypertension/hypotension, palpitations, fainting
• Respiratory: nasal congestion, wheezing
• Anaphylaxis (life-threatening allergic reaction)

Symptom triggers can include heat, cold, temperature change, friction, stress, exercise, insect and other bites/stings, environmental odors or perfumes, alcohol, contrast dyes and certain foods or medicines.

Patients may have many different symptoms and may visit multiple doctors seeking treatment. Frequently, it’s difficult to find a doctor who connects the dots to a mast cell disease.

How is mast cell disease diagnosed?

If you suspect you may have a mast cell disease, a board-certified allergist or immunologist is a good place to start. Other specialists include gastroenterologists, dermatologists, hematologists and endocrinologists.

Diagnosis involves blood tests, including serum tryptase – a marker of mast cell burden or activation – both at a baseline level and during a mast cell reaction, and 24-hour urine collections for various mast cell mediators.

Tissue biopsies for diagnosis may include a skin and/or bone marrow biopsy, endoscopy or colonoscopy of the gastrointestinal tract and specific mast cell stains. Select patients may also require genetic tests.

Bone density, bone scans and CT scans of the abdomen and chest may be necessary to assess mast cell damage.

How is mast cell disease treated?

Patients with mast cell disease experience anaphylaxis, an acute, life-threatening systemic reaction resulting from the sudden, rapid release of mediators from mast cells. Epinephrine auto-injectors are the first line of treatment, followed by transport to the ER or hospital for follow-up care.

Patients may be treated with medications to block reactivity of the mast cells or the effects of mast cell mediators. These medications include:

• H1 and H2 antihistamines
• Mast cell stabilizers (cromolyn sodium, ketotifen)
• Leukotriene inhibitors such as montelukast
• Aspirin (under direct physician’s supervision)
• Aggressive mast cell diseases may require treatment with chemotherapy.

Adults diagnosed with mastocytosis can now take a medication to stop symptoms before they can start. Avapritinib (brand name Ayvakit®) is a kinase inhibitor that is FDA-approved to treat both advanced and indolent systemic mastocytosis. It’s taken orally as a pill. The medication delivers a small molecule that attaches to the protein (called KIT D816V) that causes the abnormal mast cell. It helps stop the development of histamine that can lead to an allergic reaction. Talk with your doctor about what medication or treatment is right for you.

Patient Resources

The Mastocytosis Society: tmsforacure.org.
Mastokids: mastokids.org

Patient Stories

Gail’s Story
Mastocytosis and anaphylaxis

My husband and I had just arrived at a restaurant for dinner with his family. As we were seated, I suddenly began to feel a familiar pain in my stomach – like a rock poking my mid-torso. I felt flushed, too.

I knew then I had less than a minute before anaphylaxis struck.

My head began to buzz and my vision “grayed.” I managed to get my epinephrine auto-injector and put it in front of my sister-in-law, who is a nurse. Then … down I went, unconscious on the floor.

Due to my systemic mastocytosis – a mast cell disease that involves abnormal mast cells accumulating in various organs – I have experienced anaphylaxis like this more than a dozen times before – at work, in a store, on the side of the road.
My sister-in-law injected the epinephrine auto-injector and called my name, but I wasn’t able to respond. I felt disoriented, confused and sleepy. I eventually opened my eyes and heard someone say the ambulance was coming. My husband asked if we could be sent to the hospital where my mastocytosis specialist would be able to provide treatment.

When the ambulance arrived, the EMT put an oxygen mask on me, but I still struggled to get air. The stomach pain was all-encompassing by that point. I had a prescription protocol signed by my doctor just for this type of situation, but the EMTs said they couldn’t give me pain medicine until I’d seen a doctor.

At the hospital, the ER staff contacted my mastocytosis specialist. Doctors started an IV, adding antihistamines (Benadryl®) and morphine, and slowly the pain subsided. The last stage of the episode included uncontrollable shaking, drowsiness, chills and a feeling of overwhelming sadness.

Since the episode, my doctor adjusted my treatment plan to help slow the progression of mastocytosis-related anaphylaxis.

I ALWAYS carry my epinephrine auto-injector and the prescription protocol with me wherever I go.

Gail Barbera
The Mastocytosis Society