title: Clinical characteristics and risk profile of patients with elevated baseline serum tryptase.
abstract: BACKGROUND
  The clinical relevance of elevated basal serum tryptase (eBST ≥ 11.4 ng/ml) often remains unclear.
  
  
  METHODS
  BST was assessed in 15,298 patients attending our outpatient clinic. Frequency and severity of anaphylaxis was compared in 900 patients with eBST and 900 patients with normal BST. The prevalence of eBST was evaluated in patients with drug reactions, urticaria, gastrointestinal symptoms or venom allergy. Mast cell-associated symptoms were recorded prospectively in 100 patients with eBST and 100 controls using a standardised questionnaire.
  
  
  RESULTS
  5.9% (n=900) of 15,298 patients had eBST ≥11.4 ng/ml (mean 20 ± 21 ng/ml, 11.4-390 ng/ml). In 47% of them BST was <15.0 and in 78% <20.0 ng/ml. In patients with normal BST (4.5 ± 2.1 ng/ml), mean levels increased continuously with age (0.28 ng/ml per decade; p<0.001). Fatigue, meteorism, muscle/bone ache, vertigo, tachycardia, flush, palpitations, diarrhoea and oedema were associated with eBST (p<0.05 to <0.0001) without significant differences between slightly (11.4-20 ng/ml) or strongly (>20 ng/ml) eBST. eBST was significantly associated with adverse reactions to drugs (34%), radio contrast media (15%) and insect stings (24%) (p<0.05). Anaphylaxis was more common in patients with eBST (21% vs. 14%, p<0.001). The relative role of insect stings, drugs and food as the most important triggers was similar in patients with elevated and normal BST. Severe reactions (grade 3/4) occurred most often in subjects with BST >20 ng/ml (BST <11.4 mg/ml: 2.8%; 11.5-20 ng/ml: 5.9%; >20 ng/ml: 12.4%).
  
  
  CONCLUSIONS
  In clinical practice it appears reasonable to assess BST, besides after anaphylactic reactions also in patients suffering repeatedly from vertigo, flush, tachycardia, palpitations, oedema and nausea. Even patients with slightly eBST have a higher risk of anaphylaxis and experience more severe reactions.
authors.affiliation: FAZ - Floridsdorf Allergy Centre, Vienna, Austria.
authors.forename: C
authors.initials: C
authors.lastname: Fellinger
authors.affiliation: FAZ - Floridsdorf Allergy Centre, Vienna, Austria. Electronic address: hemmer@faz.at.
authors.forename: W
authors.initials: W
authors.lastname: Hemmer
authors.affiliation: FAZ - Floridsdorf Allergy Centre, Vienna, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Wöhrl
authors.affiliation: FAZ - Floridsdorf Allergy Centre, Vienna, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Sesztak-Greinecker
authors.affiliation: FAZ - Floridsdorf Allergy Centre, Vienna, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Jarisch
authors.affiliation: FAZ - Floridsdorf Allergy Centre, Vienna, Austria.
authors.forename: F
authors.initials: F
authors.lastname: Wantke
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens / Q000276:immunology; D000707:Anaphylaxis / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D002648:Child; D002675:Child, Preschool; D004342:Drug Hypersensitivity / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D005512:Food Hypersensitivity / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D007223:Infant; D008297:Male; D008407:Mast Cells / Q000276:immunology*; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012306:Risk; D011795:Surveys and Questionnaires; D053802:Tryptases / Q000097:blood*; D014581:Urticaria / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D014688:Venoms / Q000276:immunology; D055815:Young Adult
chemical_list: D000485:Allergens; D014688:Venoms; D053802:Tryptases
keywords: Anaphylaxis; Basal serum tryptase; Mast cell activation syndrome; Mastocytosis