A case of occupational asthma from metabisulphite in a fisherman

The objective was to describe a case of occupational asthma in a fisherman linked to the inhalation of metabisulphites, then to discuss the history and actions for prevention.

We report the case of a fisherman fishing for Dublin bay prawn (Nephrops), who suffered from asthma after being exposed to metabisulphites. This case is compared with other cases in the occupational medical literature. He was a 53-year-old male and a former smoker, who presented with dyspnoea and a very productive cough, due to both chronic exposure to metabisulphites and acute exposure to contamination due to the breakdown of the ventilation system in the trawler on which he was fishing. The symptoms appeared to be occupational. Tests carried out in the following months revealed reversible airway obstruction with non-specific bronchial hyperreactivity, while allergy tests were negative. A visit to the trawler allowed us to determine the unusual cause of exposure in the case. Other reported cases concern normal working processes causing reversible airway obstruction.

Metabisulphites are antioxidants and preservatives used in the food industry which have been identified as the causative agent in occupational asthma since the 1980s. Only two other cases have been previously reported in fishermen, however. The clinical presentation of our subject was notable for the productive nature of his cough. The appearance of symptoms after combined acute and chronic exposure made us consider an irritative pathophysiology in this asthma, as opposed to sensitization. The negative allergy testing in this subject was similar to other cases reported in the literature. Our subject alone was submitted to patch testing, which was also negative.

Our case represents occupational asthma caused by metabisulphites with clinical signs notable for the productive nature of the cough. Few cases have been reported amongst fishermen despite the significant use of this substance with irritant and sensitizing characteristics in the workplace.