Systemic Mastocytosis and Osteoporosis

By December 14, 2017The Bone Bandits

What is Systemic Mastocytosis?

You are certainly not alone if you haven’t heard of systemic mastocytosis. This condition is incredibly rare, impacting the lives of only 5-10 people out of 1 million. It involves abnormally large numbers of mast cells in multiple organs and other body tissues. Mast cells are responsible for releasing histamine during an allergic reaction, and other chemicals which help to regulate aspects of your immune system. When too many mast cells are present, these normal responses can be greatly amplified and lead to severe symptoms. As many as 50% of people with systemic mastocytosis will develop bone problems including osteoporosis.

How is Systemic Mastocytosis Diagnosed?

The most common symptom associated with this condition includes skin “spots” known as urticaria pigmentosa. When irritated by scratching, heat, or other triggers, these spots can form hives as seen with allergic reactions. Other symptoms are less specific and include itching, skin flushing, low blood pressure, abdominal pain, nausea, vomiting, diarrhea, fatigue, and headaches. Those with systemic mastocytosis are more likely to have life-threatening anaphylactic allergic reactions.

The following tests are used to make the diagnosis of systemic mastocytosis.

  • Complete Blood Count (CBC). This lab test measures the number and types of cells within your blood. Abnormalities including anemia and abnormally high levels of eosinophils (a white blood cell involved in allergic reactions and fighting off parasites) have been seen in those with systemic mastocytosis.
  • Liver Function Tests (LFTs). This lab test measures how well your liver is functioning. Elevated test numbers indicates liver injury, which may be seen in some people with the condition.
  • Serum Total Tryptase. Tryptase is an enzyme that is primarily produced by your mast cells. Abnormally high levels (greater than 20 ng/mL) are frequently seen in those with systemic mastocytosis.
  • KIT Mutation Analysis. This is a genetic test which evaluates your blood or bone marrow for a mutation commonly seen in people with systemic mastocytosis.
  • Bone Marrow Biopsy. Those with systemic mastocytosis will have abnormal mast cells in their bone marrow. Mast cells may appear spindle-shaped and clump into groups. These abnormal cells often make up more than 25% of the total number of mast cells in the bone marrow.

How Does Systemic Mastocytosis Impact Your Bones?

Mast cells release chemicals necessary for your allergic response including histamine, and also release inflammatory substances including cytokines. When these chemicals reach your bones, they increase the activity of bone breakdown osteoclast cells, which can weaken your bones over time. Even if you do not have any physical symptoms of systemic mastocytosis, you are still at risk of developing osteoporosis. Studies differ on the number of people with bone problems from the condition, but our best estimates are 33-60% develop osteopenia, and another 10-38% develop osteoporosis.

How Can Those With Systemic Mastocytosis Improve Their Bone Health?

No specific treatment is available for the disease, but antihistamines and other medications can improve your symptoms. Osteoporosis medications appear to be helpful in improving bone density and decreasing your risk of broken bones if you suffer from systemic mastocytosis.