Occupational IgE-mediated sensitization and asthma caused by clam and shrimp.
BACKGROUND
To confirm occupational asthma caused by clam and shrimp in a food company worker, the following investigation was planned in 60 other exposed workers (56 participants).


METHODS
Before the production period of clam and shrimp, a medical and occupational questionnaire was carried out and skin and RAST testing were done with common inhalants and clam, shrimp, crab, and lobster extracts. During the production period, environmental monitoring was performed with personal and general samplers; inhalation testing with methacholine was proposed to subjects with immediate skin reactivity to clam, shrimp, or both. After the production period, all subjects with an immediate skin reactivity to clam, shrimp, or both and either a history of rhinoconjunctivitis, asthma, or bronchial hyperresponsiveness were seen by a specialist.


RESULTS
Including the index case in whom occupational asthma to clam and shrimp had been confirmed, four (7%) subjects had a history of rhinoconjunctivitis and two (4%) had a history of asthma during the period of clam production, whereas three (5%) subjects had rhinoconjunctivitis and two (4%) had asthma during the shrimp production. Three (5%) subjects had immediate skin reactivity to clam, and nine (16%) subjects to shrimp. Four (7%) subjects had increased specific IgE antibodies (RAST binding > or = 3%) to clam and eight (14%) to shrimp. Significant associations were found between immunologic reactivity to clam and shrimp on the one hand and to crab and lobster on the other. Environmental monitoring demonstrated clam and shrimp on the air sampling filters. Occupational asthma caused by clam was confirmed by specific inhalation challenges in one subject in addition to the index case. These two subjects had skin reactivity and increased specific IgE antibodies to clam, shrimp, or both.


CONCLUSIONS
By including the initial subject, the prevalence of immediate sensitization is 5% to 7% to clam and 14% to 16% to shrimp. Two (4%) subjects had occupational asthma caused by clam, and one (2%) had occupational asthma caused by shrimp.
D000328:Adult; D000818:Animals; D001249:Asthma / Q000175:diagnosis / Q000209:etiology*; D049872:Bivalvia; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents; D033364:Decapoda; D004784:Environmental Monitoring; D005260:Female; D005512:Food Hypersensitivity / Q000175:diagnosis / Q000209:etiology*; D005525:Food-Processing Industry; D005541:Forced Expiratory Volume; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D008297:Male; D016210:Methacholine Chloride; D009784:Occupational Diseases / Q000175:diagnosis / Q000209:etiology*; D015995:Prevalence; D011852:Radioallergosorbent Test; D017747:Seafood / Q000009:adverse effects*; D012882:Skin Tests; D011795:Surveys and Questionnaires
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D007073:Immunoglobulin E