What is the treatment for mastocytosis?

Treatment of Mastocytosis

The treatment of mastocytosis should focus on a combination of trigger avoidance, H1 and H2 antihistamines, and mast cell stabilizers as the first-line approach to control symptoms and improve quality of life. 1

Treatment Algorithm Based on Disease Classification

Cutaneous Mastocytosis (Most Common in Children)

1. First-line therapy:

   • H1 antihistamines (diphenhydramine, hydroxyzine, cetirizine) for pruritus, flushing, and urticaria 1
   • H2 antihistamines (ranitidine, famotidine) for gastric symptoms 1
   • Oral cromolyn sodium for gastrointestinal symptoms 2

2. Trigger avoidance:

   • Temperature extremes
   • Physical stimuli
   • Emotional stress
   • Certain medications
   • Alcohol

3. Emergency management:

   • Epinephrine auto-injector for severe reactions 1

Systemic Mastocytosis

1. Symptom control:

   • Same approach as cutaneous disease with antihistamines and mast cell stabilizers 3
   • More aggressive antihistamine dosing may be required

2. Advanced/Aggressive disease:

   • Cytoreductive therapy for aggressive systemic mastocytosis 4
   • Midostaurin (100mg twice daily with food) for advanced systemic disease 5
   • Interferon-alfa for severe cases refractory to conventional therapy 5

Medication Details

Antihistamines

• H1 antihistamines: Effective for controlling pruritus, flushing, urticaria, and tachycardia 1
• H2 antihistamines: Help control gastric hypersecretion and peptic ulcer disease 1

Mast Cell Stabilizers

• Cromolyn sodium: FDA-approved for mastocytosis; improves diarrhea, flushing, headaches, vomiting, urticaria, abdominal pain, nausea, and itching 2

Cytoreductive Therapies (for Advanced Disease Only)

• Midostaurin: For advanced systemic mastocytosis with dose adjustments based on toxicity 5
• Interferon-alfa: Can be considered for severe cases refractory to conventional therapy 5
• Tyrosine kinase inhibitors: For therapy-refractory patients with severe disease 4

Special Situations

Perioperative Management

• Continue scheduled maintenance medications
• Pre-medicate with H1 antihistamines
• Safer anesthetic agents include propofol, sevoflurane, isoflurane, fentanyl, and remifentanil 5
• Avoid: Atracurium, mivacurium, and succinylcholine 5
• Have epinephrine readily available 5

Pregnancy Management

• Multidisciplinary approach with high-risk obstetrics, anesthesia, and allergy
• Continue antihistamines that are safe in pregnancy
• Avoid triggers
• Have epinephrine available for anaphylaxis
• Interferon-alfa can be considered for severe refractory cases
• Avoid during pregnancy: Cladribine and tyrosine kinase inhibitors 5

Monitoring

• Baseline serum tryptase levels before starting therapy
• Closer monitoring if tryptase >20 μg/L (indicates increased mast cell burden) 1
• Follow-up every 6-12 months to assess disease progression 1
• In children, symptoms are typically more severe in first 6-18 months after onset 1

Common Pitfalls and Caveats

• Don't withhold analgesics: Pain can trigger mast cell activation; appropriate pain management is crucial 5
• Don't delay epinephrine: For severe reactions, administer epinephrine promptly 1
• Don't use cytoreductive therapy for cutaneous disease: Generally discouraged due to benign nature and high rate of spontaneous regression in children 1
• Don't rely on skin testing for drug reactions: Skin test results are not reliable predictors of adverse reactions to drugs in mastocytosis patients 5

The treatment approach should be tailored based on disease severity, with most patients requiring only symptomatic treatment with antihistamines and mast cell stabilizers, while reserving cytoreductive therapies for those with advanced or aggressive systemic disease.