Occupational asthma in snow crab-processing workers

J Allergy Clin Immunol. 1984 Sep;74(3 Pt 1):261-9. doi: 10.1016/0091-6749(84)90256-2.


The prevalence of occupational asthma was studied in two snow crab-processing industries in operation since 1980. Before the 1982 season, all except 10 of the 313 employees were investigated by a questionnaire, prick skin tests with common allergens, crab n and crab-boiling water extracts, and spirometry. The diagnosis was confirmed in 46 (15.6%) workers (including 33 of 64 subjects with a history highly suggestive of occupational asthma in the previous seasons) by (1) specific inhalation challenges in 33 subjects (one immediate, nine dual, and 23 late asthmatic responses) and/or (2) a combination of monitoring of peak expiratory flow rates (n = 12) and significant changes in bronchial responsiveness to histamine (n = 16) as well as in spirometry (n = 18) after reappearance of symptoms on return to work. Positive skin tests to crab (p less than 0.001) and, to a lesser degree, smoking history (p = 0.03) but not atopy (p greater than 0.05) were related to the presence of occupational asthma. A high prevalence of rhinoconjunctivitis (35 of 46) and urticaria (16 of 46) was also documented in the affected individuals.

MeSH terms

  • Asthma / epidemiology*
  • Brachyura*
  • Bronchi / drug effects
  • Bronchial Provocation Tests
  • Canada
  • Fish Products
  • Food-Processing Industry*
  • Forced Expiratory Volume
  • Histamine / pharmacology
  • Humans
  • Hypersensitivity, Immediate / epidemiology*
  • Nasal Provocation Tests
  • Occupational Diseases / epidemiology*
  • Skin / immunology
  • Smoking
  • Spirometry


  • Histamine