Paul Ehrlich first described mast cells in 1877 on the basis of their unique staining characteristics and large granules. Mast cells are part of the body's immune system. Mast cells are very similar to basophil granulocytes (type of white blood cell), which are both thought to originate from bone marrow precursors expressing the CD34 molecule. The basophil leaves the bone marrow once it is mature. The mast cells, on the other hand, circulate in an immature form until they reach tissue, where they fully develop.
Mast cells are found in most tissues that are near blood vessels. They are especially prominent in the skin, mucosa of the lungs and digestive tract, as well as the mouth, conjunctiva and nose.
In the early to mid-20th Century, all forms of mast cell disease were categorized under the group referred to as mastocytosis, which is characterized by abnormal mast cell growth. Over the last 30 years, researchers have defined several different categories, and the current definitions are still evolving.
Mast cell disease is more common among children than adults. According to research, the onset of mastocytosis occurs in children younger than two years old in 55% of patients.
The exact cause of mastocytosis is unknown.
Mast cells are essential components of the inflammatory process. The mast cells may be stimulated by injury, the binding of immunoglobulin E (IgE) to receptors or by activated complement-dependent mechanisms.
Mast cells express FceRI, a high-affinity receptor for IgE. When this receptor binds to IgE, it is irreversible. As a result, the mast cells become coated with IgE. Then, IgE is produced by B-cells in the immune system.
When an allergic reaction occurs, the allergen binds to IgE, and then mast cells are subsequently activated. It appears that mast cells are activated after two or more IgE molecules bind together (crosslinking). This process, known as IgE-mediated mast cell degranulation, triggers the release of granules and hormonal mediators into the interstitium.
MAIN TYPES OF MASTOCYTOSIS
Cutaneous mastocytosis (urticaria pigmentosa): When mast cells build up in the skin, the condition is known as cutaneous mastocytosis. Skin lesions, called urticaria pigmentosa, are present in most patients with cutaneous mastocytosis. This condition primarily affects children and resolves as children reach puberty in more than 50% of pediatric cases. Symptoms usually decrease in the remaining patients as they mature into adults. The disease may progress to the more serious systemic mastocytosis in adults. When the mast cells cause a single lesion on the skin, it is known as solitary mastocytoma.
Mastocytoma (mast cell tumor): A mastocytoma is a benign skin tumor consisting of mast cells. Mastocytoma is usually present at birth or in early childhood, and in most cases, it spontaneously resolves. While this condition can occur in humans, it is seen most often in dogs and cats.
Systemic mastocytosis: Systemic mastocytosis is a rare disorder characterized by abnormal accumulations of mast cells throughout the body, especially in the bone marrow and internal organs. This form of the disease primarily affects adults. Systemic mast cell disease has been associated with several other hematologic diseases, including hypereosinophilic syndrome, Castleman disease, monoclonal gammopathy and hairy cell leukemia. Non-Hodgkin lymphoma, polycythemia vera and primary thrombocythemia have also been associated with systemic mastocytosis. While the specific incidence of systemic mastocytosis remains unknown, some studies in Great Britain reported an average of only two new cases per year, from a study population of 300,000.
Cutaneous mastocytosis (urticaria pigmentosa): Common symptoms include, facial flushing, brownish lesions on the skin, as well as welt, hive or blister formation when lesions are scratched or rubbed. In severe cases, diarrhea, increased heartbeat, headache and fainting may also occur.
Mastocytoma: Mastocytoma is usually present at birth or in early childhood. One or more red, pink or yellow bumps can appear anywhere on the skin. Rubbing or scratching the affected area causes mastocytomas to redden, swell and sometimes blister. Occasionally, patients experience flushing when the mast cells release chemicals like histamine.
Systemic mastocytosis: Since systemic mastocytosis may affect different areas of the body, symptoms may be related to the hematopoietic system, the gastrointestinal system, the skin and the immune system. Common symptoms include, abdominal pain, hives, rash, anaphylaxis, inflamed esophagus, changes in blood pressure, intestinal cramping, bloating, bone pain, itching, chest pain, liver problems, cognitive difficulties, malabsorption, degenerative disc disease, migraine headaches, diarrhea, muscle pain, dizziness, lightheadedness, nausea, osteoporosis, osteopenia, fatigue, peripheral neuropathy, paresthesias, flushing, rapid heart rate, gastroesophageal reflux, vomiting and hematological abnormalities.
Biopsy: A qualified healthcare provider may take a tissue biopsy from an organ (like the bone marrow) or the skin, to determine whether the patient has systemic mastocytosis. The tissue sample is analyzed in the lab to determine whether there is an increase in the number of mast cells.
Blood test: A physician may perform a blood test to confirm a diagnosis. A small sample of blood is taken and analyzed under a microscope to determine whether there are an increased number of mast cells in the blood.
Urine test: A urine test may be conducted. Individuals with urticaria pigmentosa will usually have elevated levels of histamine in their urine.
While there is no specific cure for the disease, children usually experience a lessening of symptoms as they grow older, and medication may help manage the symptoms.
Antihistamines: Antihistamines like diphenhydramine (Benadryl©), loratadine (Claritin©), fexofenadine (Allegra©) or cetirizine (Zyrtec©), may relieve some of the histamine-induced symptoms, such as itching and facial flushing.
Beta-2 agonists: Beta-2 agonists (like Albuterol©) may help open airways that have constricted as a result of histamine.
Corticosteroids: Corticosteroids (like prednisone) have been applied topically or inhaled to reduce inflammation of the skin.
Epinephrine: Epinephrine has been used to treat anaphylaxis associated with mastocytosis. Epinephrine opens the airways and raises the blood pressure by constricting blood vessels when excessive mast cell degranulation has caused anaphylaxis. Patients may also be admitted to the hospital to monitor blood pressure and provide breathing support.
Mast cell stabilizers: Mast cell stabilizers like cromolyn sodium (Gastrocrom©) have been used to help prevent mast cells from releasing their chemical contents. Cromolyn may help relieve symptoms including, diarrhea, flushing, headaches, vomiting, urticaria, abdominal pain, nausea and itching.
Proton pump inhibitors: Proton pump inhibitors like Protonix©, Nexium©, Aciphex©, Prevacid©, Prilosec©, and Zegarid© have been used to help reduce the production of gastric acid, which is often elevated in patients with mastocytosis. High levels of gastric acid may harm the stomach, esophagus and small intestine.
Surgery: In some cases, isolated mastocytomas may need to be surgically removed.
Currently, there is insufficient evidence available on the use of integrative therapies for mastocytosis.
Avoid exposure to known allergens.
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
- Alto, William. Cutaneous and Systemic Manifestations of Mastocytosis. American Family Physician. June 1999. View Article. Accessed March 26, 2007.
- Natural Standard: The Authority on Integrative Medicine. www.naturalstandard.com. Copyright © 2007. Accessed March 26, 2007.
- Oklahoma Mastocytosis Society. www.okmastocytosis.org. Accessed March 26, 2007.
- The Cleveland Clinic Health Information Center. Mastocytosis. www.clevelandclinic.org. Accessed March 26, 2007.
- The Mastocytosis Society. Mastocytosis/Mast Cell Activation Disorders. www.tmsforacure.org. Accessed March 26, 2007.
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