From the Guidelines
Mastocytosis patients should be managed with a multidisciplinary team approach, preferably in specialized centers with expertise in mastocytosis, and treatment should include antihistamines, H2 blockers, and avoidance of known triggers, as well as consideration of targeted therapies like midostaurin for advanced cases. The condition is characterized by the abnormal accumulation of mast cells in various tissues of the body, which can lead to symptoms such as itching, flushing, and gastrointestinal distress. According to the most recent guidelines, patients with mastocytosis should be counseled regarding signs and symptoms of disease, and should avoid known triggers of mast cell activation, such as alcohol, extreme temperatures, and certain medications like NSAIDs and opioids 1.
The use of antihistamines like cetirizine (10mg daily) or fexofenadine (180mg daily), and H2 blockers like ranitidine (150mg twice daily) can help control symptoms, and mast cell stabilizers like cromolyn sodium (200mg four times daily) may be beneficial in severe cases 1. Patients at risk for anaphylaxis should carry epinephrine auto-injectors, and targeted therapies like midostaurin (100mg twice daily) or chemotherapy may be necessary for advanced systemic mastocytosis 1.
Regular monitoring by specialists is essential, as the disease course varies widely among individuals, and referral to specialized centers with expertise in mastocytosis is strongly recommended 1. The comprehensive care of patients with mastocytosis requires a multidisciplinary team approach, involving dermatologists, hematologists, pathologists, gastroenterologists, allergists, and immunologists, and enrollment in well-designed clinical trials investigating state-of-the-art therapeutic strategies is encouraged to enable further advances 1.
Key considerations in the management of mastocytosis include:
- Avoiding known triggers of mast cell activation
- Using antihistamines and H2 blockers to control symptoms
- Considering targeted therapies like midostaurin for advanced cases
- Carrying epinephrine auto-injectors for patients at risk for anaphylaxis
- Regular monitoring by specialists and referral to specialized centers with expertise in mastocytosis.
From the Research
Definition and Symptoms of Mastocytosis
- Mastocytosis is a disorder characterized by abnormal growth and accumulation of mast cells, which contain histamine and other inflammatory mediators 2.
- The symptoms of mastocytosis can include flushing, pruritus, nausea, vomiting, abdominal pain, diarrhea, vascular instability, and headache, and are generally divided into cutaneous and systemic manifestations 2.
- These symptoms are the result of mast cell mediator release and infiltration into target organs 3.
Types of Mastocytosis
- There are two main divisions of mastocytosis: cutaneous mastocytosis (CM) and systemic mastocytosis (SM) 2.
- CM has a highly favorable clinical prognosis, while SM has a range of severity, with milder forms often remaining chronic conditions and severe forms having rapid complex courses with poor prognoses 2.
- Systemic mastocytosis can be further divided into indolent/smoldering SM (ISM/SSM) and advanced SM, which includes aggressive SM (ASM), SM with associated hematological neoplasm (SM-AHN), and mast cell leukemia (MCL) 4.
Treatment and Management
- Treatment for mastocytosis is aimed at avoiding mast cell degranulation, inhibiting the actions of constitutive mediators released by mast cells, and in severe cases, using cytoreductive and polychemotherapeutic agents 2.
- Behavioral intervention includes avoidance of triggers, such as heat, cold, pressure, exercise, sunlight, and strong emotions 2.
- Pharmacotherapy should be individualized for each patient, considering the category of disease, reduction of risk of anaphylaxis, constitutional symptoms, and comorbidities, including osteoporosis 5.
- Cytoreductive therapies are generally reserved for patients with advanced mastocytosis, but may also be considered for patients with indolent disease and recurrent anaphylactic episodes not responsive to antimediator therapies 5.
Diagnosis and Risk Stratification
- The diagnosis of systemic mastocytosis is based on the presence of multifocal clusters of spindled mast cells in the bone marrow, elevated serum tryptase level, abnormal mast cell CD25 expression, and presence of KITD816V mutation 4.
- Risk stratification is important to determine the prognosis and treatment goals for patients with systemic mastocytosis, and can be refined by identifying poor-risk mutations and using clinical and hybrid clinical-molecular risk models 4.
Treatment Options
- Treatment options for advanced systemic mastocytosis include small-molecule inhibitors that target mutant-KIT, such as midostaurin and avapritinib, as well as cladribine and interferon-α 4.
- Allogeneic stem cell transplant can be considered for patients with relapsed/refractory advanced systemic mastocytosis or those with SM-AHN 4.
- Imatinib has a limited therapeutic role in systemic mastocytosis, and is only effective in patients with imatinib-sensitive KIT mutations 4.