Clinical Manifestations
Indolent Systemic Mastocytosis
- Most common cause of adult-onset mastocytosis
- Usually associated with small monomorphic maculopapular lesions on thigh or trunk
- Anaphylaxis in 50%
Urticaria Pigmentosa
- Presents with maculopapular rash that can resemble freckles
- Usually has systemic involvement
- Darier's sign: light rubbing or scratching of a lesion will cause erythema or urticaria
Unexplained or Severe Anaphylaxis
- Anaphylaxis, usually without urticaria or angioedema
- Without a trigger, or in response to bee/wasp/etc sting
Other Syndromes
- Adult with hematologic abnormalities, splenomegaly, and weight loss
Investigations
- CBC may show cyptopenias or cytoses, including eosinophilia and circulating mast cells
- Serum tryptase, at baseline (not during an attack), which should be elevated
- Liver enzymes for possible liver involvement
- Bone dexa for osteopenia or osteoporosis
