Mastocytosis

Mastocytosis, a type of mast cell disease, is a rare disorder affecting both children and adults caused by the accumulation of functionally defective mast cells (also called mastocytes) and CD34+ mast cell precursors. People affected by mastocytosis are susceptible to a variety of symptoms, including itching, hives, and anaphylactic shock, caused by the release of histamine and other pro-inflammatory substances from mast cells. When mast cells undergo degranulation, the substances that are released can cause a number of symptoms that can vary over time and can range in intensity from mild to severe. Because mast cells play a role in allergic reactions, the symptoms of mastocytosis often are similar to the symptoms of an allergic reaction. They may include, but are not limited to Fatigue Skin lesions (urticaria pigmentosa), itching, and dermatographic urticaria (skin writing) "Darier's Sign", a reaction to stroking or scratching of urticaria lesions. Abdominal discomfort Nausea and vomiting Diarrhea Olfactive intolerance Ear/nose/throat inflammation Anaphylaxis (shock from allergic or immune causes) Episodes of very low blood pressure (including shock) and faintness Bone or muscle pain Decreased bone density or increased bone density (osteoporosis or osteosclerosis) Headache Depression Ocular discomfort Increased stomach acid production causing peptic ulcers (increased stimulation of enterochromaffin cell and direct histamine stimulation on parietal cell) Malabsorption (due to inactivation of pancreatic enzymes by increased acid) Hepatosplenomegaly There are few qualitative studies about the effects of mastocytosis on daily life. However, a Danish study from 2018 describes the multidimensional impact of the disease on everyday life. Mast cells are located in connective tissue, including the skin, the linings of the stomach and intestine, and other sites. They play an important role in the immune defence against bacteria and parasites. By releasing chemical "alarms" such as histamine, mast cells attract other key players of the immune defense system to areas of the body where they are needed.