What Is Mastocytosis?

Mastocytosis is a genetic immune disorder by which mast cells grow abnormally and build up in the skin and other organs. The condition, a type of mast cell disease, causes a number of symptoms, including flushed skin, gastrointestinal issues, and liver and spleen enlargement. Mastocytosis happens because of a gene mutation during fetal development. There’s no way to prevent it, but you can avoid triggers and find treatments that work for you.

Continue reading to learn more about mastocytosis, including how you can feel better when living with the condition. 

What Does Mastocytosis Look Like?

Mastocytosis affects roughly one to two people per 20,000 across the globe. It’s considered a rare disease. Symptoms can start in childhood or adulthood. If the condition has an onset in childhood, babies usually experience symptoms before they are 1 year old.

Mastocytosis has many possible symptoms. The symptoms depend on where the mast cells accumulate.

The most common symptoms of mastocytosis are skin changes. These can include:

• Red, flushed, and warm skin
• Pigmentation changes, or areas of the skin that have a different tone than the rest of your body
• Macule (or flat) discolored patches of skin less than 1 centimeter across
• Itchiness, also known as pruritus 
• Hives
• Urticaria pigmentosa, or raised brown patches of skin
• Blistering without a clear cause

What Are Mast Cells?

Mast cells are a type of white blood cell and part of the body’s immune system. Mast cells protect you by releasing chemicals that create an inflammatory immune response. When this happens in response to an infection or injury, it helps the body heal.

Yet, with mastocytosis, too many mast cells build up in one area of the body, such as the skin, the bone marrow, or the intestines. This can cause inflammation and discomfort in these organs. Although mastocytosis isn’t considered an autoimmune disease, it is an immune system disease.

Mastocytosis Types

There are two major types of mastocytosis:

Cutaneous Mastocytosis

Cutaneous mastocytosis affects the skin. It happens when mast cells accumulate in the skin, leading to the symptoms outlined above. People with cutaneous mastocytosis mostly experience skin-related symptoms, but adults with this variety might have other symptoms too. This type of mastocytosis is more common in children than in adults, but it can occur in people of all ages.

Systemic Mastocytosis

With systemic mastocytosis, mast cells can accumulate anywhere in the body. Patients with this type of mastocytosis might have skin symptoms or might not. There are five subtypes of systemic mastocytosis, including two that are not life-threatening:

• Indolent mastocytosis: The most common and least severe type
• Smoldering mastocytosis: For people with this type, the condition affects more than one organ and results in slightly more severe symptoms than it does for people with indolent mastocytosis.

The other three forms of mastocytosis are very serious because they can impact organ function. They can lead to a shortened life span, although this varies widely. Ask your healthcare provider about your prognosis if you have one of these types:

• Aggressive systemic mastocytosis, which causes a loss of bone density and leads to bone fractures.
• Systemic mastocytosis with an associated hematologic neoplasm, a type of blood cancer.
• Mast cell leukemia, a type of blood cancer.

What Causes Mastocytosis?

Mastocytosis results from a genetic mutation that happens when a fetus is developing. The condition isn’t inherited and doesn’t run in families. 

The mutation is related to the KIT gene. Normally, this gene acts as an on-off switch to control the production of a protein called KIT. However, the mutation that causes mastocytosis, known as KIT D816V, causes the switch to always be on. That means mast cells are always growing and active, causing them to build up within the body.

What Are the Symptoms of Mastocytosis?

In addition to the skin symptoms outlined above, other symptoms of mastocytosis can include:

• Tiredness and fatigue
• Nausea
• Abdominal pain
• Bloating
• Diarrhea
• Acid reflux
• Congestion
• Shortness of breath
• Low blood pressure
• Lightheadedness
• Headache
• Memory problems
• Depression
• Anxiety
• Severe allergic reactions, including anaphylaxis

What Can Trigger Mastocytosis Symptoms?

Many people with mastocytosis find that certain triggers make their symptoms worse. Common triggers include:

• Mold
• Insect stings
• Sunlight
• Strong odors
• Sudden temperature changes
• Vibrations
• Antibiotics
• Opioids
• Stress
• Bacterial infections

How Is Mastocytosis Diagnosed?

Healthcare providers typically start with a physical exam to diagnose mastocytosis. They’ll ask you about your symptoms and triggers. If they believe you have mastocytosis, they will likely order a biopsy. If they suspect cutaneous mastocytosis, they’ll order a skin biopsy. For systemic mastocytosis, they’ll need a bone marrow biopsy.

The biopsy looks for the appearance of mast cells and other blood markers that indicate an excess of mast cells. If you have a certain level of these markers, you meet the criteria for mastocytosis diagnosis. 

Blood tests may also help to diagnose mastocytosis.

Mastocytosis Treatment

Currently, treatment for mastocytosis focuses mostly on controlling symptoms. However, researchers are working to develop targeted therapies that can address the root cause of the condition. 

Available treatments for mastocytosis include:

• Moisturizers and a skin care routine to alleviate itchiness and other skin symptoms
• Antihistamines
• Mast cell stabilizers, medications that help control the number of mast cells in a certain area of the body

In severe cases, healthcare providers might recommend immune system therapies and chemotherapy. Treatments can also target specific systems, such as using blood transfusions to treat anemia, and osteoporosis drugs to help fight bone loss from mastocytosis. 

Complications of Mastocytosis

Mastocytosis can be very serious. If you have the condition, it’s important to work with your healthcare provider to control symptoms. Severe forms of mastocytosis can lead to blood cancer, osteoporosis, depression, and other serious conditions. Early intervention and management of other conditions that arise from your mastocytosis can help keep you healthy. 

Can You Prevent Mastocytosis?

You can’t prevent mastocytosis because the condition results from a gene mutation that happens before birth. However, you can help control your symptoms. The best way to do that is by avoiding triggers. This takes time and practice to learn what causes symptoms to flare up. You can also work with your healthcare provider (or treatment team) to develop a treatment plan that helps control your symptoms. 

What’s the Outlook for People With Mastocytosis?

Most people with mastocytosis have mild forms of the disease. They can control symptoms by avoiding triggers and taking medications without impacting their life expectancy. However, more aggressive forms of systemic mastocytosis can be deadly. 

Because this condition has such a range of severity, it’s important to have open, honest communication with your healthcare team about your specific outlook. Connecting with these organizations can also help you learn more about the condition:

• The Mast Cell Disease Society
• The EveryLife Foundation for Rare Diseases
• The U.K. Mastocytosis Support Group

Summary

Mast cells are an important part of the immune system. But when your body doesn’t stop production, mast cells can build up in your organs, leading to mastocytosis. Skin symptoms such as flushing and hives are the most common symptoms associated with mastocytosis. However, at its most serious, the condition can also impact other organs and ultimately lead to blood cancer.

If you have mastocytosis, talk to your healthcare provider about avoiding triggers (such as heat, certain foods, or pollutants) and using a treatment regimen to manage your symptoms. In most cases, mastocytosis doesn’t impact life expectancy. If you’re worried or overwhelmed by the diagnosis, talk to your doctor about your specific prognosis and outlook.