Mast cell activation is the process by which the immune cells, mast cells, release inflammatory chemicals like histamine in response to triggers, causing inflammation.
This can be a normal, protective immune response to threats like infections or allergens, but can also become pathological in Mast Cell Activation Syndrome (MCAS), where cells are inappropriately triggered, leading to chronic, multisystem symptoms.
Triggers can include allergies, infections, stress, certain foods, medications, and temperature changes, and symptoms can affect the skin, gut, lungs, and other systems.
Mastocytosis
In some individuals, the disease may present with single, isolated symptoms due to the release of mast cell mediators, including redness, skin itching, headache, stomach cramps, diarrhea, nausea, palpitations, and a drop in blood pressure that can lead to unconsciousness.
At other times, the disease may manifest as a combination of different symptoms that produce a disease picture similar to anaphylaxis. Symptoms such as irritability, difficulty concentrating, and personality changes also occur.
In people with systemic mastocytosis, wasp and bee stings can cause a range of symptoms, including local swelling with itching and burning, hives (urticaria), and anaphylactic shock with effects on blood circulation. Insect venom-triggered anaphylactic reactions are much more common in people with systemic mastocytosis than in others, affecting about a quarter.
The disease can affect the bones, and osteoporosis, which carries an increased risk of fractures, is a common consequence. Local thinning of the bones (lysis) and abnormally dense bones (osteosclerosis) also occur, but are less common.
