Mast Cell Activation Syndrome; This literature marketed information has been received from the authors in a published article title as stated below and refers to a 21-year-old female patient.   The patient presented with reports of significant constipation, frequent ear infections, dermatographism, and unusual sensitivities/reactivities to various sensations from early in infancy. When she was 7 years old, a bull's-eye rash (without a witnessed tick bite) was seen on her, and she was diagnosed with Lyme disease and treated with amoxicillin for two weeks. At age 8 years-old, misophonia emerged. At age 12 years-old, aquagenic urticaria emerged. Menarche came at age 13, but she has never had regular cycles. Focal vaginal pain precluded the use of tampons. At 15 years-old, she received the full series of three Gardasil vaccinations. Three months after the last vaccination, with no other changes in her regimen in the interval, she developed a non-specific illness. Within days, exhaustion emerged and has persisted ever since. Motion sickness emerged too. Dysmenorrhea emerged, leading to a clinical diagnosis of endometriosis. Depression emerged; a trial of duloxetine did not help and only worsened her fatigue. Methylphenidate was tried but only worsened her misophonia. About a year after completing the Gardasil series, she was diagnosed with Lyme disease again. A prolonged course of doxycycline seemed to ease her fatigue somewhat, but she also began experiencing eczema and a burning sensation about her skin. When she was 18 years-old, she was diagnosed with scoliosis. She was also started on an oral contraceptive for her irregular periods, but soon developed severe irritability and depression. Evaluation discovered elevated cortisol. Multiple endocrinologic evaluations, including contrasted brain/pituitary MRI, failed to identify a cause. She developed severe hives and dizziness from the MRI contrast. The oral contraceptive was discontinued, and the irritability, depression, and cortisol elevation resolved. Further evaluation for weight gain, irregular menses, acne, and mild malepattern alopecia (without hirsutism) led to a diagnosis of polycystic ovarian syndrome (PCOS). She was also diagnosed with hypothyroidism. At 19 years-old, bouts of vertigo and postprandial tachycardia emerged, fatigue worsened, and nausea as well as anorexia emerged. Laboratory testing confirmed non-celiac gluten sensitivity. Dietary gluten eliminationhelped some of her gastrointestinal symptoms, but she continued to be quite symptomatic. At 21 years-old, she started having allergic reactions, with erythema and pain, to the application of deodorant. She was evaluated at 21 years for complaints of persistent fatigue, difficulty concentrating, depression, amenorrhea which had persisted for six months, and frequent urticaria from multiple triggers. She was being treated by another physician at that time for multiple concurrent infections (Lyme disease, ehrlichiosis, bartonellosis, and babesiosis) with several antibiotics, including dapsone, azithromycin, and rifampin, to no clear benefit. Laboratory testing was notable for a mildly elevated high-sensitivity C-reactive protein (CRP), a normal total IgE level, an off-the-scale elevated anti-IgE-receptor antibody level, a normal anti-IgE antibody level, normal tryptase, normal chromogranin A, mildly elevated plasma histamine (2.2 ng/mL, normal 0.02.0), and a normal diamine oxidase level. Mast cell activation syndrome (MCAS) was suspected.    MCAS-targeted treatment was initiated with trials of various H1 blockers. She had a moderate response to loratadine. All the H2 blockers she tried seemed to worsen her alopecia. Low-dose naltrexone (LDN), titrated up to 4.5 mg once daily, improved her depression. Oral cromolyn 100 mg four times daily significantly improved her nausea and intermittent bloating. Due to persistent urticaria, omalizumab (300 mg subcutaneously every four weeks) was tried, and within three months she had a notable improvement in her fatigue and a resolution of her urticaria (with prompt relapse if treatment was delayed). She has been stable on her regimen of loratadine, cromolyn, LDN, and omalizumab for two years.  Literature report:  Upon internal review the of Mast Cell Activation Syndrome (MCAs) was considered as medically significant.   This is one of several report from the same literature article.   A copy of the published article is attached as further documentation of the patient's experience.