Mast Cell Diseases are diseases that impact mast cells.

What is a mast cell?

A mast cell is a type of cell found in the connective tissues in the body. They are located in the skin, lining of the gastrointestinal tract, bone marrow, airway, and other organs. Mast cells contain granules that store chemicals. These chemicals are released as part of the body's normal response to injury or exposure to something the body deems as a threat, like an allergen. The chemicals released can cause a host of allergic and non-allergic presenting signs and symptoms. [ x ]

There are numerous types of Mast Cell Disease.

 The most common is called Mastocytosis.

  • mast - in reference to a mast cell
  • cytosis - a condition in which there are more than the normal number of cells

Therefore, Mastocytosis is a condition in which there is an abnormal number of mast cells in the body.

There are two types of Mastocytosis: [x]
  1. Cutaneous Mastocytosis: where mast cells numbers are increased in the skin, but not elsewhere in the body. It causes abnormal lesions, spots, and bumps on the skin. 
  2. Systemic Mastocytosis: Primarily effecting adults, mast cells proliferate in the tissues, like the skin, organs, and bones. 
There are various forms of Systemic Mastocytosis. The disease is classified as either indolent, which means it is slow-growing, or aggressive, which means it is fast-growing. As the number of mast cells builds up in an organ, the symptoms of the disease may get worse. Systemic Mastocytosis can become cancerous, resulting in Mast Cell Leukemia or Mast Cell Sarcoma. [x]

Also under the umbrella of Mast Cell Diseases is:

  1. Mast Cell Activation Syndromes (MCAS, MMAS): presenting much like Systemic Mastocytosis symptom wise, it is defined as having normal number of mast cells (or very mild proliferation) that have an activation problem. The mast cells constantly "misbehave" and release their chemicals over anything and everything.  It is a condition with signs and symptoms involving the skin, GI tract, cardiovascular, respiratory, and neurologic systems. It can be classified into primary, secondary, and idiopathic.[x] 
What do mast cells do? 

As an immune cell, mast cells release a variety of enzymes and chemicals when the body is injured or exposed to a trigger (like an allergen). Mast cells release histamine, which is why antihistamines are vital drugs for sufferers. In addition, mast cells also release an enzyme called tryptase. In people with Mast Cell Disease, the high levels of histamine, tryptase, and other chemicals in the body lead to painful symptoms. Tryptase levels can be measured in the blood, but this test can be unreliable, as low tryptase levels do not necessarily rule out mastocytosis. 

An increase in mast cells and/or improper activation causes excessive mediator release when mast cells are triggered. Common triggers are foods, medications, stress, heat or cold, airborne and applied chemicals from perfumes, lotions, detergents, hair products, soaps, etc. Once mast cells are triggered, they can continue to degranulate, or release chemicals, over literally anything...even water. It is similar to an allergy where the triggers constantly change; although, mast cell patients do not have to test positive for true IgE allergies.

Symptoms include:
  • Flushing
  • Hives and/or Itching
  • (Pre)Syncope (Fainting/Blackouts)
  • Chronic Pain (Bone Pain, Muscle Pain, Nerve Pain)
  • Nausea, Vomiting, Reflux, GERD
  • Alternating Diarrhea and/or Constipation
  • Anemia
  • Abnormal Electrolytes 
  • Organ Inflammation (Swelling of Spleen, Liver, Pancreatitis, etc.)
  • Bladder Cystitis 
  • Low or High Blood Pressure
  • Tachycardia and/or Bradycardia 
  • Headaches
  • Dystonia 
  • Partial Paralysis Episodes
  • Tremors, Tics, Seizure Disorders
  • Life Threatening Anaphylaxis (NOT ALL CASES)
And More. 

What causes Mast Cell Disease? 

Mastocytosis is an orphan genetic disease. An orphan disease is one that is very rare. Genetic means that it involves hereditary transmission and/or some form of mutation. In most cases of Mast Cell Disease, especially in Mastocytosis, usually this mutation affects the KIT gene, which normally encodes for a protein in the receptor tyrosine kinase family of proteins. KIT protein signaling is important for the development of certain cell types, including mast cells (which are a type of immune cell). [x

Since mast cells live in connective tissues, Mast Cell Diseases (often related to Mast Cell Activation), are commonly diagnosed along with connective tissues disorders, like Ehlers Danlos Syndrome. Mediator release from mast cells compromise the connective tissues, which is the glue that holds the body together resulting in joint laxity often seen in Ehlers Danlos Syndrome type 3 and Joint Hypermobility Syndrome. The complete understanding of the genetic and environmental link is still unknown.