Dareen D. Siri, MD, FAAAAI, FACAAI is a board-certified allergist and immunologist practicing at Midwest Allergy Sinus Asthma, based in central Illinois. She talked with CheckRare about a unique, rare disorder called systemic mastocytosis.
Systemic mastocytosis involves the proliferation of mast cells, which can accumulate in various areas of the body. The early signs of mastocytosis can be quite variable, said Dr. Siri, and include cutaneous spots or an extensive rash; gastrointestinal symptoms like diarrhea, bloating, or perceived new food intolerance; or even anaphylactic reactions.
Patients may present with what looks like an allergic reaction, she added, and some patients do not have a very high mast-cell burden. This variability may pose a challenge to accurate diagnosis. Most patients experience some level of fatigue. Patients may also complain of bone pain or “feeling like they have the flu every day.”
Dr. Siri pointed out that these patients may have many symptoms. A convincing allergic reaction that gives a strong gastrointestinal and perhaps an anaphylactic reaction, may suggest to clinicians that mast-cell proliferation is the root of the problem.
Once a clinician suspects systemic mastocytosis as the cause, a key step is obtaining a blood test for increased tryptase levels, which can serve as “a good screener, at least.” However, this is not sufficient alone. A bone marrow biopsy and histology will confirm the diagnosis. An acquired (not inherited) genetic variant (KIT D816V), is present in the stem cells of nearly all patients with systemic mastocytosis.
Systemic mastocytosis comes in two forms—aggressive and indolent. She cautioned that indolent mastocytosis should not necessarily be considered a disorder with a mild course. The rash can be quite extensive and the potential for anaphylactic reactions can result in loss of consciousness and falls.
Exciting new therapy offers promise to long-suffering patients that this chronic condition can be treated at the source: targeting the genetic mutation responsible. Finally, patients have more than antihistamines and leukotrienes to alleviate their symptoms.
Dr. Siri concluded that “It’s important for patients to know that this condition is acquired during their lifetime,” and it is not inherited or congenital. Even though the body is now making abnormal mast cells, patients can live a normal, full life.
To learn more about systemic mastocytosis and other rare autoimmune conditions, visit https://checkrare.com/diseases/autoimmune-autoinflammatory-disorders/