Introduction to Mast Cell Diseases

If you or anyone you know have struggled with a multi-symptom, chronic condition that seems to elude a proper diagnosis, then you might have heard someone mention a mast cell disorder or disease. Mast cell diseases have a laundry list of symptoms because they can involve multiple systems in the body. This is a quick introduction to how mast cell diseases affect various systems in our bodies:

“Common constitutional symptoms of Mast Cell Activation Syndrome (MCAS) include fatigue, malaise, suddenly feeling hot or cold, inappropriate sweats, flushing, unprovoked changes in appetite or weight.

Dermatologic: Common dermatologic symptoms of MCAS include rashes and lesions of many sorts (e.g., migratory and waxing/waning patches of redness, acne-like folliculitis), itching, flushing (sometimes migratory), swelling (often migratory), pregnancy-like purplish lines/bands (“striae”) about the abdomen, flanks, armpits and/or hips, redness in the track of a scratch (“dermatographism”), poor healing, and nail issues (e.g., brittleness, longitudinal ridging, “white spots” (dyshydrotic eczema); ingrown nails, too, are seen sometimes).

Ophthalmologic: Common eye symptoms include irritation and inflammation of the eyes (often described as feeling “sandy,” “gritty,” “dry,” and usually without any clear infection to account for it), usually fairly brief episodes of difficulty focusing vision, eyelid tremors/tics (“blepharospasm”), and unusual sensitivity to either bright lights or lights of certain colors.

Otologic: Common ear symptoms include ringing in the ears and irritation and inflammation in the ears. Less common are a sense of chronic fluid build-up in the ears, hearing loss (one-sided or two-sided), or uncomfortable heightened hearing sensitivity.

Nasal/Oral: Common oral and nasal symptoms include ulcers and pain (sometimes described as “burning”), white patches about the tongue or other surfaces, swelling of the tongue or other surfaces, sensitivity and/or deterioration of the teeth and/or gums despite reasonably good attention to dental and gum hygiene, alterations in the sense of taste, throat irritation/soreness/inflammation and/or hoarseness (without any infection clearly being present to account for it), difficulty swallowing, congestion of the sinuses and nose, sores up inside the nose, and nasal and post-nasal drip.

Lymphatic: Common symptoms of the lymphatic system include a diffusely migratory, waxing/waning enlargement and/or irritation/inflammation of the lymph nodes, typically about the neck and in either armpit and to either side of the groin, but possibly in other areas, too (including in the spleen, the body’s largest lymph node, which often is felt as a left upper quadrant abdominal discomfort).

Respiratory: Common respiratory tract symptoms include painful discomfort at any level of the respiratory tract, bronchitis, cough, shortness of breath (often modest and inconstant; “from time to time, I just suddenly can’t catch a deep breath” is the most common phrasing MCAS patients use to describe their shortness of breath). Frank wheezing is not seen all that often, and when it’s present during the episodes of shortness of breath, it’s usually fairly subtle. Obstructive sleep apnea can happen, too, even in patients who are not morbidly obese.

Cardiovascular: Common cardiovascular symptoms and findings include palpitations, lightheadedness, unexplained/unexpected hypertension and/or hypotension, palpitations, chest discomfort or pain (usually non-anginal in character), vascular malformations such as aneurysms or hemorrhoids or hemangiomas or telangiectasias).

Gastrointestinal: Common gastrointestinal symptoms include pain/inflammation (often migratory) in one or more segments of the GI tract, gastroesophageal reflux, abdominal discomfort/pain, abdominal bloating (usually shortly following meals), unexplained/unexpected fluctuations in appetite and/or weight, queasiness, nausea (vomiting is relatively uncommon), and diarrhea (or “soft stools”) and/or constipation (often alternating). Blood in the stool can happen but is pretty uncommon. Urinary: Common urinary symptoms include unusual frequency of urination, difficulty initiating urination, inability to fully empty the bladder, and painful urination (as if a urinary tract infection is present, except that testing can’t find clear evidence of infection). Flank or abdominal pain from kidney stones can happen but is not all that common. Blood in the urine can happen but is pretty uncommon.

Genital Tract: Other than decreased libido and erectile dysfunction and possible fertility issues, genital tract symptoms are uncommon in men but may include inflammation of the prostate or other parts of the genital tract. In women with MCAS, genital tract symptoms are common and include an inflamed and/or itchy vulva and/or vagina (often mistakenly attributed to, and treated as, bacterial or yeast infections even though no evidence of infection can be found), inappropriate/dysfunctional uterine/menstrual bleeding, and painful intercourse. Endometriosis seems somewhat common, too.

Pregnancy: Women who have MCAS also can have decreased libido and fertility challenges. Women with MCAS who become pregnant sometimes experience early miscarriages, excessively severe or prolonged vomiting (“hyperemesis gravidarum”), the assortment of high blood pressure and other problems collectively called pre-eclampsia, and pre-term labor. In delivery, women with MCAS sometimes find difficulties tolerating, or getting relief from, anesthetics.

Muscular: Common muscular symptoms include migratory pain and weakness.

Skeletal: Common skeletal symptoms include migratory pain. Fractures are uncommon but can happen from loss of skeletal strength, and these include vertebral fractures which can lead to loss of height.

Joint: Common joint symptoms include migratory pain; migratory swelling and even redness, too, can happen, but usually are not as prominent as pain.

Neurologic: Common neurologic symptoms include headache (including migraines), episodic lightheadedness/dizziness/vertigo (which can happen either when getting up or even when lying down or sitting or after already been up for a while) (total loss of consciousness can happen but is much less common than lightheadedness), tingling/numbness (most commonly in the hands and feet but potentially anywhere), weakness, tics/tremors, and a wide variety of sleep disruptions (most commonly insomnia and frequent waking and non-restorative sleep but also excessive sleep, sleepwalking or sleep talking, sleep paralysis, or night terrors).

Psychiatric: Common psychiatric symptoms include anxiety (sometimes even to the point of panic), depression, mood lability, anger, attention deficit, and a wide variety of aspects of cognitive dysfunction, most commonly issues with memory, word-finding and concentration. “Dissociation” or “depersonalization” is occasionally seen. Psychotic behaviors (e.g., auditory or visual hallucinations) are fairly uncommon.

Endocrinology: Common endocrinologic/metabolic issues include delayed or premature puberty, excessively painful and/or irregular periods, excessive menstrual bleeding, weak bones, thyroid abnormalities, high cholesterol or triglycerides, high glucose levels (usually diagnosed as diabetes mellitus) or low glucose levels (sometimes rapid alternation among normal and low and/or high levels), and selective abnormalities in absorbing or transporting or using certain important minerals and vitamins (e.g., iron).

Hematologic: Common hematologic and clotting system issues include modest abnormalities in blood counts, easy bruising, and easy bleeding (for example, excessive menstrual bleeding or easy nosebleeds). Excessive blood clotting is less common than easy bruising/bleeding.

Immunologic: Common immunologic issues include prolific and/or unusual sensitivities/reactivities/allergies, impaired healing, an unusual extent of autoimmune diseases, increased susceptibility to infection, and difficulty recovering from infection (Clinical Manifestations of Mast Cell Activation Syndrome By Organ Systems)

Dr. Lawrence Afrin, D. T. D. (2019, February 4). Clinical manifestations of mast cell activation syndrome by Organ Syst. drtaniadempsey. Retrieved February 4, 2022, from

Because mast cell diseases are multi-system, each patient will present differently with their unique set of symptoms. Furthermore, Mast Cell Activation Syndrome (MCAS) is only one syndrome under the heading of mast cell diseases:

“Mast cell disease(s) (MCD) is the term used by mast cell specialists in the U.S. and internationally for all mast cell diseases. This covers each variant: systemic mastocytosis (SM), cutaneous mastocytosis (CM), smoldering mastocytosis (SSM), advanced disease variants, mast cell activation syndrome (MCAS) and hereditary alpha tryptasemia (HaT) [or hereditary alpha tryptasemia syndrome (HaTS)]. Since MCD covers all variants of mast cell disease, it is inclusive of every patient suffering from any type of mast cell disease. The American Initiative in Mast Cell Diseases (AIM) also chose their name to represent all mast cell diseases. MCAD is an older term used by some that meant mast cell activation disorder. Some physicians and patients still use the term disorder as we all slowly transition to disease.” (

Overview & diagnosis – TMS – the mast cell disease society, inc. TMS. (2021, October 27). Retrieved February 4, 2022, from

What then is a mast cell disease? We know that the symptoms are numerous, multi-systemic, and chronic:

“Mast cell diseases are caused by the proliferation and accumulation of genetically altered mast cells and/or the inappropriate release of mast cell mediators, creating symptoms in multiple organ systems.2 The three major forms of mast cell diseases are mastocytosismast cell activation syndrome (MCAS), and Hereditary Alpha tryptasemia (HAT) or [Hereditary Alpha tryptasemia Syndrome(HATS)]. Mast cell diseases can cause tremendous suffering and disability due to symptomatology from daily mast cell mediator release, and/or symptoms arising from infiltration and accumulation of mast cells in major organ systems. Although systemic mastocytosis is a rare disease,3 those suffering with MCAS have recently been increasingly recognized and diagnosed. As a result, patients with MCAS appear to represent a growing proportion of the mast cell disease patient population.4, 5 It is important to note that the process of mast cell activation can occur in anyone, even without a mast cell disease, as well as in patients with both mastocytosis and MCAS.6” (

Overview & diagnosis – TMS – the mast cell disease society, inc. TMS. (2021, October 27). Retrieved February 4, 2022, from

Among the three major forms of mast cell disease, there are variants:

I. Mastocytosis: Systemic mastocytosis (SM) and its variants, mast cell leukemia, cutaneous mastocytosis (CM) and its variants, and mast cell sarcoma

II. Mast Cell Activation Syndrome (MCAS): Primary MCAS, Secondary MCAS, Idiopathic MCAS

III. Hereditary alpha-tryptasemia (HαT) (and the accompanying syndrome HαTS, which is to say that one can be diagnosed with the inherited alpha-tryptasemia genetic variant but not express any symptoms associated with it. The syndrome associated with hereditary alpha-tryptasemia manifests as a cluster of symptoms associated with chronically elevated levels of tryptase. Some people have the genetic variant called hereditary alpha-tryptasemia (HαT) but never go on to develop the syndrome (HαTS). Others, however, do. This is the difference between HαT and HαTS.)

Further reading:

The Mast Cell Disease Society, Inc

Dr. Tania Dempsey: What is Mast Cell Activation Syndrome?

Never Bet Against Occam: Mast Cell Activation Disease and the Modern Epidemics of Chronic Illness and Medical Complexity by Lawrence B. Afrin M.D., Kendra Neilsen Myles, et al.

The Mast Cell Disease Primer

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