Quaternary ammonium compounds and occupational asthma.

OBJECTIVE: Quaternary ammonium compounds, among which benzalkonium chloride is one of the best-known, are commonly used as antiseptics, disinfectants, detergents and preservatives. They can cause occupational asthma, which however, has been rarely reported so far, despite wide use of these products. We report three such cases. Possible mechanisms causing asthma are discussed, taking into account their characteristics. METHODS AND RESULTS: Our patients, all female nurses, manifested asthma symptoms upon handling disinfectant solutions containing benzalkonium chloride. Work-related fall in PEFR was observed in all of them. The diagnosis was confirmed by challenge tests where the patients were exposed, in a closed chamber, to suspected disinfectant contained in a tray. All of the women developed early or delayed symptoms upon exposure. Similar challenge tests to placebo or other disinfectants devoid of quaternary ammonium compound were negative. CONCLUSION: These three cases, in addition to others reported in the literature, point out an as yet poorly known etiology of occupational asthma to quaternary ammonium compounds in hospital employees. The exact mechanism of the action remains unexplained.

[Occupational asthma in an agricultural setting]. / L'asthme professionnel en milieu agricole.

The prevalence of asthma in a farming environment is significant (from 3-7.7% according to various studies). The clinical picture has not been specified. The responsible agents are multiple and polysensitization frequent. Numerous substances of vegetable origin may be a cause, pollens, moulds, cereals, oil and protein producing plants, fibrous textiles, diverse plants and wood, etc. Amongst substances of animal origin the most frequent allergens incriminated are: allergens from mammals (horses, cattle, pigs), allergens from chickens and birds, arthropod allergens, insect allergens. Amongst chemical products those which are at risk to the respiratory system include insecticides, herbicides, fungicides, antibiotics and antiparasites. The diagnosis of the occupational character of asthma is sometimes difficult because of other causes of lung diseases in farm workers. The aetiological diagnosis is achieved by the clinical history, cutaneous tests, a level of specific serum IgE, and bronchial provocation tests which contrary to asthma in the industrial environment are not fundamental to the diagnosis except where chemical products are suspected. The mechanisms are sometimes intricate (IgE dependant mechanisms, non-specific liberation of histamine, activation of complement, intervention of endotoxins and pharmacological mechanisms...). Prevention may be carried out on behalf of the victim (for example wearing filtration masks in dusty work) and also carry out various methods to reduce the level of exposure to the allergen.

[Asthma, rhinitis and urticaria following occupational exposure to cyanoacrylate glues]. / Asthme, rhinite et urticaire secondaires à l'exposition professionnelle aux colles cyano-acrylates.

Cyanoacrylate glues are more and widely used in the industry because of easy handling and great sticking power. These very volatile and chemically reactive glues may not only cause contact eczema, but also rhinitis and asthma. Nineteen cases of asthma have been reported to date. We report two new cases of occupational asthma as well as one case of urticaria, a clinical symptom not yet described, to our knowledge. In the three cases, diagnosis was made based on a compatible medical history and positive realistic exposure tests. The mechanism is still unknown, due to the physical properties of cyanoacrylate glues; in fact, it is not possible to perform prick tests or specific IgE measurements. Besides the usual preventive measures, maintaining a relative humidity greater than 55% seems to induce polymerization of free monomers of alkyl cyanoacrylate, thereby reducing their volatility. Rhinitis and asthma due to cyanoacrylate glue may receive compensation as occupational diseases in France.

[Occupational asthma: medical and social prognosis]. / Asthme professionnel: pronostic médical et social.

The medical and social prognosis of occupational asthma has only been assessed with retrospective studies. The main findings are analyzed here. The wide range of methods used to obtain a positive diagnosis of occupational asthma and more or less complete eviction of the causal agent hinder interpretation of the results. Nevertheless, the findings reported in 15 studies focusing on the medical prognosis have shown that in 70% of the cases, occupational asthma remains symptomatic after eviction. The number of years the asthma existed at diagnosis is higher in subjects who remain symptomatic after eviction. In most patients with occupational asthma, the absence of eviction leads to accentuation of the obstructive syndrome and non-specific bronchial hyperreactivity. When the occupational disease has been recognized, the social-professional consequences unfortunately often include loss of employment and lower revenue.

[Occupational asthma: an experimental asthma. Apropos of isocyanate-induced asthma]. / L'asthme professionnel: un asthme expérimental. A propos de l'asthme aux isocyanates.

Isocyanate-induced occupational asthma is a model of experimental asthma related to the environment. Many of its features are identical with those of allergic asthma by sensitization to air-borne allergens. Exposure to isocyanate before the first symptoms of asthma varies from a few weeks to several years. The prevalence of isocyanate-induced asthma has been estimated at 5 to 25%. Atopy is found in less than 30% of the cases. A significant increase of HRBNS can be demonstrated in most patients, but it may be absent. It may also fluctuate with the working periods or after a bronchial provocation test with isocyanate. Elimination of this compound reduces the HRBNS level in only one quarter of the cases. Delayed or biphasic reactions are frequent: 30 to 60% depending of the authors. An early diagnosis followed by total elimination may result in complete cure, but more than 50% of the patients remain symptomatic and with HRBNS. An IgE-dependent mechanism can be demonstrated in about 20% of the cases. The course of isocyanate-induced asthma is interesting in that the same phenomena are probably observed in chronic asthma resulting from repeated exposures to environmental allergens.