Patients with mastocytosis may or may not have constitutional symptoms, which include weight loss, pain, nausea, headache, malaise, or fatigue. These symptoms may be due to uncontrolled proliferation of mast cells or involvement of distinct organs, such as the stomach and intestines, or bone or bone marrow. Constitutional symptoms also can result from high systemic levels of mast cell mediators. The severity of symptoms varies from mild to life-threatenting, and recurrent presence of the following symptoms, singly or in combination, may be recorded as part of the diagnosis of mastocytosis: syncope, hypotensive shock, nausea, vomiting, diarrhea with abdominal pain, uterine cramps or bleeding, shortness of breath, dysphonia, ECG alterations that can include ischemic ST-waves, arrhythmais and atrial fibrillations, peptic ulcer disease, severe bone pain, urticaria, angioedema, severe headache, impaired level of consciousness, a sense of impending doom, pruritus, and flushing. These symptoms may appear in a compressed time frame (as in anaphylaxis) or as chronic conditions.
It should be noted that the manifestation of anaphylaxis or similar symptoms among infants and preschoolers may be more difficult to identify. For example, in one case an infant with underlying SM presented with recurring spells of apnea.