Occupational asthma caused by allergy to pigs' urine.

Occupational asthma caused by allergy to pigs' urine We report a case of asthma due to occupational exposure to pigs. The cause of the symptoms was exposure to the urine of the animals. This was proved by provoking acute asthma with an inhalation challenge of an extract of pigs' urine at a concentration of 1 g/l. On a second occasion this asthmatic response was blocked by prior treatment with 40 mg sodium cromoglycate (Intal). The patient's serum contained specific IgE antibody to the urine extract which was not found in unexposed controls. Case report The patient, a 21-year-old eczematous woman who enjoyed a vigorous sporting life, playing squash and hockey to a high standard, had not suffered respiratory symptoms since the age of 3. During her second year at university studying agricultural sciences her class visited a pig house. Within two to three minutes she had to leave because she felt as if she was being "stifled with a plastic bag." She took about an hour to recover her breath and within a few minutes her eczema had begun to itch, and this took a further two hours to settle. One year later, within five minutes after starting to watch a laparo-tomy on a pig, she again became short of breath. Her only other exposure to these animals had been during a visit to the pig house in her first year, when she remained symptomless. Skin-prick tests yielded positive reactions to grass, house-dust mite, horse, cat, dog, and pork extract. Pigs' urine (50 ml) was filtered, sterilised, and freeze dried as described1 and reconstituted in Coca's solution at 01 and 1 0 g/l. Skin testing produced a 3 mm weal with the solution at 1 0 g/l. After inhaling a nebulised dose (0-0015 g) for one minute her forced expiratory volume in one second (Vitalograph) fell by 70 % from 2-3 to 0-7 1. The same test was conducted one week later after 40 mg of sodium cromoglycate had been given by inhalation 10 minutes before the challenge. On this occasion her forced expiratory volume in one second fell by nearly 28 %0 from 2-5 to 1-8 1. In each case recordings were made for a further five hours throughout