systemic mastocytosis

Introduction

Also see mastocytosis.

Epidemiology

• rare

Pathology

• mast cell proliferation & organ infiltration

Clinical manifestations

• 1/2 of patients may have no skin findings
• weight loss
• weakness
• episodes of flushing (histamine release)
  • flushing may be accompanied by: headache, wheezing/dyspnea, diarrhea
• cardiovascular: tachycardia, hypertension, syncope
• GI: nausea/vomiting, diarrhea, malabsorption, portal hypertension
• bath pruritus (itching after hot bath)
• peptic ulcer
• ascites
• osteopenia

Laboratory

• serum tryptase > 20 ng/mL (< 11.4 ng/mL is normal)
  • often elevated at baseline as well as during an episode
• complete blood count:
  • anemia
  • leukocytosis
  • eosinophilia
• prostaglandins in urine
• see mastocytosis

Differential diagnosis

• alpha-gal syndrome
  • serum tyrptase may be elevated during acute episode
    • basal levels are normal

Management

• treatment is primarily symptomatic with a goal of preventing mast cell activation
  • prevention & treatment of anaphylaxis
  • pruritus & flushing
  • diarrhea & intestinal malabsorption
• glucocorticoids to control malabsorption, bone pain, ascites, & to prvent anaphylaxis
• epinephrine for acute anaphylaxis
• histamine H1 receptor antagonists to control symptoms of anaphylaxis
  • diphenhydramine, hydroxyzine
  • aspirin may be useful if H1 blockers are not effective
• ketotifen (mast cell stabilizer)
• cromolyn is used for decreasing bone pain & headaches & for improving skin symptoms (flushing, pruritus)
• H2 receptor blockers or proton pump inhibitor for peptic ulcer
• psoralen ultraviolet A therapy for pruritus
• aticholinergics for diarrhea
• interferon alfa-2b may be useful in patients with osteopenia

More general terms

• mastocytosis