The dangers of the workplace have been recognized for many centuries. In the third and fourth century, B.C., Hippocrates discussed with his pupils the issue of work related disease, admonishing them to observe the environment of their patients. In the second century, A.D., a Greek physician named Galen was among the earliest physicians to discuss the problems of miners, tanners, chemists and others. He and many other physicians of that time believed that inhaling smoke from burning sulfur was the best treatment for asthma. These physicians often sent their patients to the slopes of Mt. Aetna to inhale the volcano’s fumes.
In 1713, Bernardo Ramazzini, who many consider the father of modern occupational medicine, wrote, “…we must admit that the workers in certain arts and crafts sometimes derive from them grave injuries, so that where they hope for a subsistence that would prolong their lives and feed their families, they are too often repaid with the most dangerous diseases.” The industrial revolution moved workers from the safety of their homes into factories that were dark and poorly ventilated. Unfortunately, work conditions were extremely poor, and individuals frequently became ill due to occupational exposures. With the enactment of child labor laws and occupational safety laws, work conditions in the United States finally improved. Unfortunately, the first air quality standards were not published until the early 1900s. In 1946, the American Conference of Governmental and Industrial Hygienists published its initial list of 140 substances it considered potentially hazardous to workers. It took nearly 20 years, however, for the National Institute for Occupational Safety and Health to be established. This agency has assumed a primary role in providing recommended standards to the U.S. Occupational Safety and Health Administration for safe occupational exposures.
The respiratory tract is the most commonly affected organ system in occupational disease, because it represents a port of entry for irritating and intoxicating agents. A large number of chemicals and organic dusts have been identified as causing occupational asthma in the workplace. In some parts of the world it has become the most common lung disorder, although in other geographic areas occupational asthma is rare. One of the difficulties in determining how many people worldwide have this condition is the lack of a universally accepted definition of occupational asthma. In the U.S., occupational asthma is described as reversible obstruction of the airways, caused by inhaling dusts, vapors, gases or fumes either manufactured or present in the workplace. The most important characteristic of this condition is that the airways respond to a known sensitizer or inducing agent. Once symptoms begin, inhaling these substances can result in asthmatic symptoms.
A patient with occupational allergies and asthma usually develops symptoms after a period of sensitization-in other words the worker’s immune system must have several exposures to develop an immune response. The worker does not experience symptoms the first time he or she is exposed to the irritating substance, but does so after weeks or months of exposure. After sensitization has occurred, the worker may experience symptoms at work or home. Many people with occupational asthma have delayed reactions, with coughing, wheezing and chest tightness occurring many hours after exposure. It is more common, however, for workers with occupational allergies or asthma to experience nasal or respiratory symptoms in the workplace. Symptoms typically worsen during the hours at work, and improve when the patient is home. Usually, symptoms worsen by the end of the work week and will often improve significantly during vacation periods.
Sources of Occupational Allergies and Asthma
More than 200 industrial agents have been found to cause occupational allergies and asthma. They are categorized by their molecular size. Veterinarians, animal handlers, farmers and laboratory workers may be exposed to high molecular weight allergens such as animal proteins in animal dander (skin flakes), feathers, fur, saliva or urine. Food can also be a source of occupational allergic reactions. Pharmaceutical workers, delivery people and people who process food are exposed to shellfish, eggs, and coffee beans, all known to be potentially allergenic. Common fungi such as Aspergillus, Alternaria and penicillium may cause allergic reactions to woodworkers and people who work with heating, ventilation and air conditioning. Pharmaceutical agents such as antibiotics, psyllium or ipecac have caused allergic reactions in physicians, pharmacists, nurses and pharmaceutical workers. Exposure to seemingly innocuous substances such as latex in gloves also may cause allergic reactions. Workers in plastic and paint industries are often exposed to substances such as acid anhydrides or isocyanates, which can cause allergic nasal and respiratory disease.
Once a person has been identified as having an occupational allergic reaction, the treatment of choice is removal of the individual from the workplace. In rare cases, a respirator or mask may protect an individual from exposure. In most cases, however, removal is advisable. Once the exposure is discontinued, the allergic re action is usually reversible. Fortunately, the majority of occupational asthmatic conditions will regress completely if diagnosis is timely and the worker does not have any further exposures. On occasion, workers in some industries may have persistent lung impairment if they are not protected from exposure or removed from the work place soon enough.
Although we have known about occupational allergic reactions for centuries, there is still much to be learned. What were once considered to be safe levels of exposure to certain substances are now recognized as potential causes of disease. It is essential for industry and the medical community to help promote healthy work environments. The public must realize that while allergic individuals-those with allergies, asthma or eczema-are at in creased risk, they are not the only ones who can develop allergic responses to occupational substances. Many nonallergic people experience allergic reactions in the workplace. If you feel you are experiencing an allergic reaction to a substance in the workplace, it is essential that you discuss it with your employer and health care provider as soon as possible. If you feel you are experiencing an allergic reaction to a substance in the workplace, it is essential that you discuss it with your employer and health care provider as soon as possible