Because of the widespread anomalies that exist in so many tissues, relating to mast cell, the symptoms are often inflammatory, arise acutely, or even chronically developmentally. They may persist, be waxing and waning and reemit and relapse. Because it is difficult to find neoplasia or mastocytosis, persons with MCAS do not seem to "fit" into any recognizable syndrome. "Yet disability is common, sometimes severe."
“Routine” diagnostics often yield normal or equivocal results, or mild to moderate, but ephemeral, abnormal- ities. Presenting symptoms usually are subtle to moderate but may be severe or even life-threatening (eg, non- atherosclerotic myocardial infarction [often unrecognized as the vasospastic allergic angina of Kounis syndrome], end-stage renal failure, refractory diarrhea), leading to “exhaustive,” nondiagnostic testing, whereupon psycho- somatism is commonly misdiagnosed (especially if pre- sentation includes classic neuropsychiatric symptoms).1,2 Reflecting mutational heterogeneity, MCAD can present opposite abnormalities in different patients (eg, diarrhea vs constipation, polycythemia vs anemia) or in a given patient at different times (eg, alternating diarrhea and constipation) or simultaneously (eg, coexisting osteopo- rosis and osteosclerosis).1,2 Acute “flares” or “spells” are common, often occasioning urgent evaluations that, although necessary to rule out other illnesses, frequently are unrevealing, heightening suspicions of psychosoma- tism. Commonly, many idiopathic diagnoses accrue (and respond poorly to treatment) (eg, fibromyalgia, chronic fatigue, neurogenic pain, IBS, hypermobility-type Ehlers- Danlos syndrome, postural orthostatic tachycardia, histamine intolerance, dysautonomia, anxiety/panic, interstitial cystitis [itself often misdiagnosed as culture- negative urinary tract infection]). Some yet-undiagnosed patients with MCAD have definitive comorbidities (eg, sickle cell anemia or obesity) blamed for many symptoms despite difficulty of attribution, by known (patho)biological pathways, of such symptoms to such ailments.1,2
Aberrant reactivities may be prolific, odd, and, when medication related, directed against excipients, not active ingredients. Some “allergies” (eg, to iodine or even water!) may seem psychosomatic until the recognition of excipient (eg, povidone in iodine solution) or physical (eg, temperature) triggers.
Complete history taking helps to establish suspicion for MCAD. History must include a thorough systems review, as many patients with MCAD have ailed for so long that they accept much of their illness as “normal,” or they tire or become wary, after so many nondiagnostic evaluations or suspicions of psychosomatism, of reporting certain symptoms."
Any of the following symptoms may be attributed to MCAD.
| System | Potential manifestations of MCAD (most are chronic, low-grade; some are persistent, but many are either episodic or fluctuant) |
| Constitutional | Fatigue, malaise, asthenia, “chronic fatigue syndrome”, subjective and/or objective hyperthermia and/or hypothermia, “sense of feeling cold much of the time”, sweats/diaphoresis (not always nocturnal), flushing, plethora or pallor, increased or decreased appetite, early satiety, weight gain or loss, pruritus, chemical and/or physical environmental sensitivities (often odd) |
| Dermatologic/ integument | Rashes and lesions of many sorts (classic urticaria pigmentosa, “freckles”, telangiectatic/angiomatous lesions, xerosis, warts, tags, folliculitis, ulcers, dyshidrotic eczema, diffusely migratory but sometimes focally persistent patchy macular erythema), pruritus (often diffusely migratory, sometimes aquagenic), flushing, angioedema, striae, dermatographism, hair thinning and alopecia, onychodystrophy (brittle nails, longitudinal ridges), poor healing |
| Ophthalmologic | Irritated eyes, increased or decreased lacrimation, suffusion, conjunctivitis, episodic difficulty focusing, lid tremor/tic (blepharospasm), solar sensitivity, infectious or sterile inflammation |
| Otologic/osmic | Infectious or sterile otitis externa and/or media, hearing loss or hyperacusis, tinnitus, otosclerosis, dysosmia, coryza, congestion |
| Oral/oropharyngeal | Pain or irritation (sometimes “burning”), leukoplakia, fibrosis, lichen planus, ulcers, sores, angioedema, dental decay, dysgeusia, throat tickle/discomfort/irritation/pain, post-nasal drip |
| Lymphatic | Adenopathy, usually sub-pathologic and often waxing/waning in size, sometimes asymptomatic but not uncommonly tender, sometimes focal, sometimes migratory, pathology usually shows reactive lymphocytosis or sometimes an atypical non-specific lymphoproliferative disorder; left upper quadrant discomfort (likely from release of mediators from splenic mast cells with or without detectable splenomegaly) |
| Pulmonary | Rhinitis, sinusitis, pharyngitis, laryngitis, bronchitis, pneumonitis (often confused with infectious pneumonia), cough, dyspnea (often low-grade, inconstant, “I just can’t catch a deep breath” despite normal pulmonary function tests), wheezing, obstructive sleep apnea, pulmonary hypertension |
| Cardiovascular | Presyncope (lightheadedness, weakness, dizziness, vertigo) and/or syncope (patients may have been diagnosed with postural orthostatic tachycardia syndrome or neurocardiogenic syncope), hypertension and/or hypotension, palpitations, dysrhythmias, chest discomfort or pain (usually non-anginal in character), coronary and peripheral arterial atherosclerosis/spasm/infarction, idiopathic acute or chronic heart failure (e.g., takotsubo), aneurysms, hemorrhoids, varicosities, aberrant angiogenesis (hemangiomas, arteriovenous malformations, telangiectasias), migratory edema (often non-dependent and with normal cardiac and renal function) |
| Gastrointestinal | Aerophagia, angioedema in any segment of the luminal tract, dysphagia (often proximal, possibly due to pharyngeal angioedema), bloating/gas, pain/inflammation (often migratory) in one or more segments of the luminal tract (from esophagitis to proctitis) and/or one or more solid organs (e.g., hepatitis, pancreatitis), queasiness, nausea, vomiting (sometimes “cyclical”), diarrhea and/or constipation (often alternating), malabsorption (more often selective micronutrient malabsorption than general protein-calorie malabsorption), ascites either from portal hypertension and/or peritoneal serositis; gastroesophageal reflux disease (often “treatment-refractory”) and inflammatory/irritable bowel syndrome are common pre-existing diagnoses |
| Genitourinary | Inflammation (often migratory) in one or more segments of the luminal tracts (ureteritis, cystitis, urethritis, vaginitis, vestibulitis) and/or one or more solid organs (e.g., nephritis, prostatitis), chronic kidney disease, endometriosis, chronic low back pain or flank pain or abdominal pain, hydronephrosis (likely from ureteral angioedema), infertility, erectile dysfunction, decreased libido; in the appropriate setting of multisystem morbidity, miscarriages should prompt consideration of antiphospholipid antibody syndrome potentially due to MCAD |
| Musculoskeletal | Clinical myositis, often diffusely migratory (fibromyalgia is a common pre-existing diagnosis), subclinical myositis (i.e., asymptomatic elevated creatine kinase not otherwise explained), arthritis (typically migratory), joint laxity/hypermobility (patients may have been diagnosed with Ehlers-Danlos Syndrome Type III), osteoporosis/osteopenia, osteosclerosis, sometimes mixed osteoporosis/osteopenia/osteosclerosis; MCAD-driven musculoskeletal pain not uncommonly is poorly responsive to non-steroidal anti-inflammatory drugs and narcotics |
| Neurologic | Headache (esp. migraine), presyncope and/or syncope, peripheral (usually distal) sensory and/or motor neuropathies including paresthesias, tics, tremors (typically resting), chronic inflammatory demyelinating polyneuropathy, seizure disorders (can be “treatment-refractory”), pseudoseizures, dysautonomia |
| Psychiatric | Mood disturbances (e.g., anger, depression), bipolar affective disorder, attention deficit-hyperactivity disorder, post-traumatic stress disorder, anxiety and panic, psychoses, memory difficulties, word-finding difficulties, other cognitive dysfunction, wide variety of sleep disruptions |
| Endocrinologic/meta-bolic | Abnormal electrolytes (including magnesium) and liver function tests, delayed puberty, dysmenorrhea, endometriosis, osteosclerosis and/or osteoporosis, hypothyroidism, hyperthyroidism, dyslipidemia, hyperferritinemia, selective vitamin and/or other micronutrient deficiencies, weight change, possibly diabetes mellitus |
| Hematologic/coagu-lopathic | Polycythemia or anemia (may be macrocytic, normocytic, or microcytic), leukocytosis or leukopenia, chronic (usually mild) monocytosis or eosinophilia or basophilia, thrombocytosis or thrombocytopenia, arterial and/or venous thromboembolic disease, “easy” bruising/bleeding; in mast cell activation syndrome the marrow usually does not show increased (or even flow-cytometrically aberrant) mast cells; marrow histology often read as normal or as unspecified myelodysplastic/myeloproliferative syndrome; standard cytogenetic studies are almost always normal or show culture failure |
| Immunologic | Type I, II, III and IV hypersensitivity reactions, increased risk for malignancy, autoimmunity, impaired healing, increased susceptibility to infection, elevated or decreased levels of one or more isotypes of immunoglobulin; modest monoclonal gammopathy of undetermined significance not uncommon |
A concise, practical guide to diagnostic assessment for mast cell activation disease
(World Journal of Hematology: Lawrence B Afrin, Gerhard J Molderings)