Mast cells (MCs) are immune cells present in most tissues throughout the human body, especially connective tissue, skin, intestinal lining cardiovascular system, nervous system, and reproductive organs. Historically, we thought of mast cells only in relation to an allergic or anaphylactic response. However, there is increasing evidence that MCs play a role in a host of inflammatory, infectious, and functional disorders of the lungs, eyes, skin, joints, and gastrointestinal tract (i.e., irritable bowel syndrome, inflammatory bowel disease, and infectious disorders of the digestive tract). MCs have been shown to have a profound role in immune activation that left unchecked may develop in autoimmunity and other disorders, such as postural orthostatic tachycardia syndrome (POTS).

MCs produce and store in their cytoplasm a series of chemical mediators (i.e., histamine, interleukins, prostaglandins, cytokines, chemokine and others), which they release when the body is exposed to a perceived threat. Triggers may be medications, foods, supplements, hormones, opioids, physical or emotional stressors, cold temperature, heat, pressure, noxious odors, chemicals, insect bites, trauma or environmental toxins. Frequently, mast cell activation syndrome is associated with CIRS (chronic inflammatory response syndrome) in response to biotoxins, such as mold, inflammagens, and lyme-related toxins.

Without MCs prompt response to threats, we would not be able to heal from wounds. However, overactivation of MCs can cause excessive release of chemical messenger molecules which trigger local and systemic effects, such as:

  • increased permeability of blood vessels causing inflammation and swelling
  • contraction of smooth muscle generating stomach cramps and heart palpitations
  • increase mucous production triggering congestion, sneezing, etc.
Symptoms associated with Mast Cell Activation Syndrome
  • headaches
  • brain fog
  • low blood pressure
  • fatigue
  • skin rashes/hives
  • swelling/edema
  • flushing
  • itching
  • abdominal pain
  • nausea/vomiting
  • diarrhea
  • wheezing
  • shortness of breath
  • heart palpitations
  • anxiety, difficulty concentrating

(See Keith Berndtson’s ( slide.)

Diseases Associated with Mast Cell Activation Syndrome

Virtually, every organ is affected by the MCs upregulation. When several organ systems are involved, MC activation syndrome might be the underlying cause of symptoms. It is especially important to be able to recognize the constellation of clinical features because response to treatment is often excellent.