To be diagnosed with occupational asthma, several criteria have to be met. First of all, the individual must have an exposure at the workplace to specific agents that cause the employee to have an asthmatic reaction. It should be an exposure that is unique to the workplace, specific at the workplace and quantifiable at the workplace.
Secondly, an individual needs to have a diagnosis of asthma. Asthma is determined by a change in pulmonary function when exposed to the agent. In other words, once the individual is at the workplace and has constant exposure to the agent, the pulmonary function test should be different than they would be when the patient is not in the vicinity.
Thirdly, there should be no underlying intrinsic other origin of the symptoms other than the workplace exposure.
Occupational asthma can develop without a prior history of asthma. The specific mechanism for asthma occurring from exposures in non-residential buildings with poor indoor air quality are not known but generally follow allergic and nonallergic processes. When recognized and treated early, occupational asthma is usually reversible. The only sure way to prevent the worst consequence of occupational asthma, which is permanent lung damage, is to completely avoid whatever is causing the condition.
Signs and symptoms of occupational asthma include wheezing, coughing, shortness of breath, chest tightness, nasal congestion and eye irritation. Symptoms generally develop shortly after exposure to the workplace substance that causes it and may worsen as the exposure progresses. Often as the work week progresses so do symptoms with abatement of symptoms over the weekend or during vacations.
Causes of occupational asthma include six main categories of substances: animal substances, chemicals, enzymes, metals, plant substances and respiratory irritants. There are then three main processes involved in its development: direct irritation, allergic sensitization and pharmacological reaction. Determining whether or not an individual has occupational asthma is done with the same diagnostic testing used to diagnose non-occupational asthma. That testing involves a thorough medical history, description of symptoms and possible exposures, pulmonary function tests, spirometry measurements, allergy testing and workplace testing.
The longer the exposure the worse symptoms will become. Left untreated, occupational asthma can cause permanent lung damage. The best treatment is to completely avoid the work place and the substance that is causing the symptoms.