Natural history of occupational asthma: Relevance of type of agent and other factors in the rate of development of symptoms in affected subjects

New occupational allergen in citrus farmers: citrus red mite (Panonychus citri)

“…In the latter instance, 50% of patients develop symptoms within the first 2 years of exposure. 15 In subjects continuously exposed to the causative agent, the latent period was shorter than in those who were intermittently exposed. 21 In the present study, citrus farmers had been intermittently exposed to CRM-derived allergens, which have two peaks in late spring and mid fall, and are minimal during other periods, especially winter.…”

“…The duration of latency seems to depend on the nature of the causal agent, and exposure duration and intensity to a sensitizing agent. [15][16][17][18][19][20] In subjects with occupational asthma caused by high molecular weight agents, the latent period was longer than in those caused by low molecular weight agents. In the latter instance, 50% of patients develop symptoms within the first 2 years of exposure.…”

Health hazard evaluation and technical assistance report: HETA-93-0436-2569, Trus Joist MacMillan, Deerwood, Minnesota.

“…(25) Smoking history and allergy do not appear to be risk factors for the development of isocyanate-induced asthma. (22,26) Studies of the natural history of occupational asthma (27) indicate that, although improvement is often noted after exposure to the precipitating agent is terminated, symptoms and bronchial hyperresponsiveness may persist for many years or indefinitely. Persistence of chronic asthma appears to be related to the duration of an individual's exposure following onset of the disease and may also be related to the severity of the asthmatic reaction.…”

“…Most sensitized individuals will exhibit eosinophilia. (20,(22)(23)(24) After a diagnosis of reversible airways obstruction has been determined, the next step is to determine whether it is work-related and/or related to isocyanate exposure. This determination can be made according to the following criteria.…”

HETA 94-0312-2512, Square D Company, Oshkosh, Wisconsin.

“…[34][35][36][37][38][39][40][41][42] Currently, the prevalence of diisocyanate-induced HP in the worker population is unknown, and is considered to be a rare event when compared to the prevalence rates for diisocyanate-induced asthma. 8 Whereas asthma is an obstructive respiratory disease usually affecting the bronchi, HP is a restrictive respiratory disease affecting the lung parenchyma (bronchioles and alveoli).…”