title: Indolent systemic mastocytosis with elevated serum tryptase, absence of skin lesions, and recurrent severe anaphylactoid episodes.
abstract: BACKGROUND
  In contrast to aggressive mastocytosis, patients with indolent systemic mastocytosis (ISM) usually present with urticaria pigmentosa-like skin lesions. In those who lack skin lesions, mastocytosis is often overlooked or confused with endocrinologic, allergic, or other internal disorders.
  
  
  RESULTS
  We report on a 33-year-old male patient in whom severe hypotensive episodes occurred after contact with ants or yellow jackets. Since no specific IgE was detected, the serum tryptase concentration was measured and found to be clearly elevated (70 ng/ml). Consecutive staging and examination of the bone marrow revealed ISM. The patient was advised to circumvent insect contact, to take antihistamines on demand, and to carry an epinephrine self-injector for emergency events. In a retrospective analysis of 40 patients seen between 1988 and 2003, only 2 had a life-threatening mediator-related episode before ISM was diagnosed.
  
  
  CONCLUSIONS
  Our report confirms the diagnostic value of tryptase in patients with suspected mastocytosis. In addition, the report suggests that the lack of typical skin lesions does not exclude an indolent form of mastocytosis even if the serum tryptase is clearly elevated. Finally, our case further shows that mastocytosis can be an important differential diagnosis to be considered in patients with unexplained anaphylactoid or other mediator-related symptoms.
authors.affiliation: Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Florian
authors.forename: Maria-Theresa
authors.initials: MT
authors.lastname: Krauth
authors.forename: Ingrid
authors.initials: I
authors.lastname: Simonitsch-Klupp
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Sperr
authors.forename: Robert
authors.initials: R
authors.lastname: Fritsche-Polanz
authors.forename: Karoline
authors.initials: K
authors.lastname: Sonneck
authors.forename: Manuela
authors.initials: M
authors.lastname: Födinger
authors.forename: Hermine
authors.initials: H
authors.lastname: Agis
authors.forename: Alexandra
authors.initials: A
authors.lastname: Böhm
authors.forename: Friedrich
authors.initials: F
authors.lastname: Wimazal
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Horny
authors.forename: Peter
authors.initials: P
authors.lastname: Valent
mesh_terms: D000328:Adult; D000707:Anaphylaxis / Q000097:blood / Q000150:complications* / Q000209:etiology; D000818:Animals; D000941:Antigens / Q000096:biosynthesis / Q000276:immunology; D001000:Ants; D001317:Austria / Q000453:epidemiology; D001853:Bone Marrow / Q000276:immunology / Q000473:pathology; D002460:Cell Line; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007299:Insect Bites and Stings / Q000150:complications*; D008297:Male; D008407:Mast Cells / Q000276:immunology / Q000473:pathology; D034721:Mastocytosis, Systemic / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D009000:Monocytes / Q000737:chemistry; D009154:Mutation / Q000276:immunology; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis / Q000235:genetics; D012008:Recurrence; D012697:Serine Endopeptidases / Q000097:blood*; D012871:Skin Diseases / Q000175:diagnosis; D053802:Tryptases; D014863:Wasps
chemical_list: D000941:Antigens; D019009:Proto-Oncogene Proteins c-kit; D012697:Serine Endopeptidases; D053802:Tryptases