Systemic mastocytosis (pronounced mass-toe-sigh-TOE-sis), or SM for short, is a rare disorder that causes the body to make too many abnormal mast cells. Mast cells are white blood cells that aid the immune system and help fight off illness. When these cells are activated, it can result in symptoms similar to an allergic reaction. A severe allergic reaction, known as an anaphylaxis, can cause severe inflammation and organ damage.

About Non-Advanced Systemic Mastocytosis

Non-advanced systemic mastocytosis (NonAdvSM) accounts for about 90% of all SM cases.

NonAdvSM is a lifelong condition where your body produces too many mast cells that accumulate in various organs, particularly your bone marrow, skin, and digestive system. These mast cells can release chemicals like histamine, causing allergy-like symptoms throughout your body.

What are the three types of non-advanced systemic mastocytosis?

• Indolent Systemic Mastocytosis (ISM) is the most common form. Symptoms can range from mild to severe and often include skin involvement. This form typically remains stable over time.
  
  
• Smoldering Systemic Mastocytosis (SSM) involves a higher number of mast cells than ISM and may cause more pronounced symptoms.
  
  
• Bone Marrow Mastocytosis (BMM) primarily affects the bone marrow, with fewer skin symptoms. It’s often discovered during evaluation for other conditions.

What symptoms might I experience with non-advanced systemic mastocytosis?

Common symptoms include skin issues like itching and flushing, digestive problems such as abdominal pain and diarrhea, fatigue, headaches, and difficulty concentrating (“brain fog”). Some people also experience anxiety, bone pain, and sensitivity to temperature changes.

Signs of Non-Advanced Systemic Mastocytosis

Symptoms may include:

Itching, skin lesions, skin redness, or warmth (flushing)

Wheezing, shortness of breath

Fatigue

Allergic reaction

Abdominal pain, bloating, diarrhea, nausea, or vomiting

Brain fog, dizziness, memory issues, mood changes, or trouble concentrating

Bone pain and/or fractures

What causes non-advanced systemic mastocytosis?

Most cases are caused by a genetic mutation called KIT D816V, found in about 95% of adults with SM. This mutation typically develops during your lifetime rather than being inherited from your parents.

Will non-advanced systemic mastocytosis affect my life expectancy?

NonAdvSM typically doesn’t shorten life expectancy. While it can significantly impact your quality of life and daily activities, with proper management and care, many people with NonAdvSM live full, active lives.

Can my non-advanced systemic mastocytosis progress to advanced systemic mastocytosis?

While NonAdvSM generally remains stable, a small percentage of cases may progress over time. Regular monitoring with your healthcare team helps ensure any changes are detected early.

How can I manage life with non-advanced systemic mastocytosis?

Focus on identifying and avoiding your personal triggers, communicating effectively with your healthcare team familiar with mast cell disorders, connecting with support communities, and developing strategies for managing symptoms during flares.