Fatigue, rashes, foggy thinking, joint pain, palpitations, itchiness, insomnia, thyroid problems, gas and bloating, swollen lymph nodes.... When confronted with this list of symptoms, health care professionals are often boggled and cannot make sense of how they are all related. In fact, many patients are labeled as having a psychosomatic illness; that it’s “all in their head”. These patients can be puzzling even to integrative doctors, who treat their guts, prescribe chelation therapies, drastically change their diet and lifestyle, and treat chronic infections, only for the patients to not feel better at all.
If you can relate to any of this, you may be suffering from the ever more common Mast Cell Activation Syndrome (MCAS). MCAS describes a process in which mast cells become overreactive. It is a chronic, multi-systems illness which can mimic many other diseases.
(Please note that MCAS is very different from mastocytosis, a rare form of blood cancer.)
What are mast cells?
Mast cells are a part of our immune system; they are white blood cells that live in our tissues. They are found in all tissues but are most prominent in the mucosa (our first line of defense to the outside world), and vascular tissue. The effect of mast cells is therefore most often seen in the tissues of the gastrointestinal tract, skin and genitourinary system, but MCAS can present in all body systems. Each mast cell contains over 200 chemical signals, or cytokines, the most well-known of which is histamine.
What is the function of the mast cell?
The main job of the mast cell is to connect the immune system to the nervous system, both through direct contact and indirectly, using cytokines. It is the mast cell’s job to sense things from our environment and tell our nervous system whether or not these things are a threat. If we are exposed to an infection or a toxin, for example, the mast cell activates and releases cytokines to tell the nervous system to ramp up and eradicate the threat.
Mast cell activation syndrome results from hyperreactive mast cells.
Things start to go wrong when the mast cell becomes over responsive to “non threats”. It can see something as simple as a food, cold temperatures, a stressful event or even a smell as being threatening. It then overreacts and explodes, releasing all of the symptom-causing cytokines. What catalyzes this is not often known. In secondary MCAS, the triger can be something like an infection from mold, lyme, or a virus. Primary MCAS is usually from earlier on in life and is possibly caused by ‘mutations’ in the mast cells. Our world is now filled with so many potential toxic triggers that in a susceptible individual, it is only a matter of time before the mast cells start to misbehave. When we don’t know what the cause of MCAS is, whether it be primary or secondary, we call it idiopathic MCAS. The good news is that the management for each kind of MCAS is very similar.
How do we diagnose MCAS?
With difficulty is the short answer.
Only about 10 of the 200 mediators that the mast cell releases can be measured. Additionally, these mediators are in and out of the bloodstream within seconds, even though their effects are long-lasting.
MCAS is often a clinical diagnosis, looking at the various symptoms that a patient has. It may be the case that the lab tests we are able to do come back as negative, but a diagnosis can still be made. However, diagnosing by symptoms is not straight-forward. Patients may present with seemingly unrelated symptoms, expressed in all systems in the body.
The symptoms will depend on which mediators are released, and in what tissues they are released. The symptoms do not always make sense and are not reproducible by the same trigger. For example, on one day a certain food may trigger a cytokine storm, but on the next day, that same food has no effect. The symptoms sometimes come on without any known trigger, and the effect can be acute or chronic, local or remote. The unpredictability of the symptoms is very scary for patients and many of them have been misdiagnosed for years, or even their whole lives.