Mastocytosis: Understanding a Rare Mast Cell Disorder

Mastocytosis is a rare condition caused by an abnormal buildup of mast cells in the skin and, in some cases, throughout the body. Unlike common allergic reactions that occur suddenly and resolve, mastocytosis is considered chronic, meaning symptoms may persist or recur over time.

Mastocytosis develops when mast cells gradually increase in number and accumulate in body tissues over several years. Mast cells are part of the immune system and are normally found in areas such as the skin, lungs, and intestinal lining. These cells release histamine, a chemical responsible for allergic symptoms and stomach acid production. As mast cell numbers increase, histamine levels also rise—leading to ongoing symptoms.

In some individuals, mastocytosis is linked to a genetic mutation. In others, the exact cause remains unknown.

Types of Mastocytosis

Mastocytosis may affect only the skin or involve multiple organs.

Cutaneous Mastocytosis

• More common in children

• Mast cells accumulate primarily in the skin

• Often appears in infancy or early childhood

• Presents as small, reddish-brown spots or raised bumps, a condition known as urticaria pigmentosa

• Lesions may itch, especially when rubbed or scratched

Many children experience improvement or resolution of symptoms as they grow older.

Systemic Mastocytosis

• More common in adults

• Mast cells accumulate in internal organs such as:

  • Stomach and intestines

  • Liver and spleen

  • Bone marrow and lymph nodes

• Organs may function normally at first, but heavy mast cell infiltration can impair function over time

• In rare cases, excessive mast cell buildup in bone marrow can reduce red blood cell production and lead to serious blood disorders

Signs and Symptoms of Mastocytosis

Skin symptoms are the most common and may include:

• Persistent itching

• Flushing or redness

• Hives after rubbing or scratching lesions

Symptoms may worsen due to:

• Sudden temperature changes

• Physical exertion or exercise

• Friction from clothing

• Alcohol, hot beverages, or spicy foods

• Certain medications, including NSAIDs

Scratching lesions can trigger histamine release, causing the skin to redden and swell rapidly.

Management and Symptom Control

Cutaneous Mastocytosis

• Antihistamines (H1 blockers) are commonly used to reduce itching and flushing

• In children, no further treatment is often required

• Adults with persistent skin symptoms may benefit from:

  • Corticosteroid creams

  • Controlled ultraviolet light therapy

Systemic Mastocytosis

There is no cure, but symptoms can be managed:

• H1 antihistamines reduce itching, flushing, and skin reactions

• H2 blockers reduce stomach acid production and help manage gastrointestinal symptoms

• Avoidance of known triggers is essential

Why Mastocytosis Matters in First Aid Awareness

Although mastocytosis is rare, individuals with this condition may be at increased risk of severe allergic-type reactions, including anaphylaxis in some cases. For Canadians, this highlights the importance of:

• Recognizing early warning signs

• Knowing when to activate emergency medical services

• Understanding the role of antihistamines and epinephrine

First aid and CPR training improves confidence in responding to unexpected allergic or systemic reactions.

Important Disclaimer

Educational Use Only
The information provided on mastocytosis is intended for general education and first aid awareness only. It does not replace professional medical advice, diagnosis, or treatment. Anyone experiencing severe allergic symptoms, difficulty breathing, or signs of anaphylaxis should seek immediate emergency medical care.

Participation in first aid and CPR training supports early recognition and response but does not substitute medical treatment.