Occupational contact dermatitis and asthma are two of the most common work-related health issues facing workers worldwide today, say experts who presented their latest research on the topic at a recent annual meeting of the American College of Allergy, Asthma & Immunology, in Miami Beach, Fla.

"In many countries, occupational contact dermatitis ranks first among occupational diseases," says Dr. Donald Belsito, clinical professor of dermatology at the University of Missouri, in Kansas City, Mo. "The incidence of occupational contact dermatitis in the United States is underestimated by 10 to 50 times."

Occupational contact dermatitis involves an acute or chronic inflammation of the skin from exposure to chemical, biological, or physical agents in the workplace. Belsito says registries are incomplete, the incidence rate is underreported, and differences in reporting across countries further complicate data on its global prevalence.

"After the skin, the lungs are the most commonly affected organ in the workplace," says Dr. Emil J. Bardana Jr., professor of medicine in the allergy-immunology division at Oregon Health and Science University, in Portland, Ore.

Occupational asthma, which is characterized by inflammation of the airways with coughing, wheezing, or shortness of breath, is caused by inhalation of dusts, gases, fumes, vapors, or allergens in the workplace. "Somewhere between 9 and 15 percent of asthma is probably work-related," says Bardana.

With both contact dermatitis and asthma, the reaction can be allergic or caused by irritation.

In the case of occupational contact dermatitis, 80 percent of cases occur on the hands, which may become dry, chapped, patchy, red, and scaly.

Most often, the problem is caused by chronic irritation from water, soaps, solvents, and greases. It can take months and even years of exposure before symptoms occur.

In the case of occupational asthma, spray paint is one common trigger, but anything from chemicals to welding fumes to soybean dust can be a culprit.

"There are hundreds of potential triggers of occupational asthma," says Dr. Paul A. Greenberger, professor of medicine in the allergy-immunology division at Northwestern University's Feinberg School of Medicine, in Chicago. "It can be triggered by animals, minerals, or vegetables."

Asthma symptoms may worsen during the workweek for people with occupational asthma. In cases of allergic occupational asthma, there often is a latency period before symptoms occur. When an irritant causes the airway reaction, there is a sudden onset, usually within 24 hours of exposure.

"In the United States, agricultural and manufacturing have particularly high rates of occupational contact dermatitis," says Belsito. Other jobs associated with higher rates of contact dermatitis include mechanic, metal worker, cleaner, health-care worker, construction worker, cosmetologist, baker/cook, and housekeeper.

There is crossover between industries related to a high incidence of contact dermatitis and jobs linked to occupational asthma.

"One European study showed the highest risk occupation for asthma was cleaning—a broad group, including janitorial, custodial, and commercial," Bardana says. "When broken down by industry, we have some specific numbers. For example, 30 percent of animal lab workers, 10 percent of snow crab processors, and 9 percent of bakers are affected by occupational asthma."

Other industries with higher rates of occupational asthma include health care, printing, painting, wood mill, beauty salon, farming, and textile.

Diagnosing occupational asthma is complicated in that several respiratory conditions have similar symptoms, including reactive airway dysfunction syndrome, chronic obstructive pulmonary disease, and hypersensitivity pneumonitis.

Difficulty also arises in differentiating between new cases of asthma caused by a work environment, meaning occupational asthma, and the worsening of symptoms in workers who had asthma prior to their jobs.

"Oftentimes, there is aggravation of pre-existing asthma that gets blamed on what's going on at the job," Bardana says. "Many people who have asthma don't even know it. For example, sometimes military recruits don't find out they have asthma until they go through training."

Asthmatics might have an increase in symptoms due to cold air or exercise, two common triggers.

"If someone is working outside in Alaska, the worker may think his or her work has made asthma worse, but in reality, it was the exercise or cold air rather than the work," Bardana says.

Avoidance is best defense

With both occupational asthma and contact dermatitis, avoiding the irritant or allergen is the best line of defense.

"Eighty percent of workers recover from occupational contact dermatitis without impairment when managed correctly," Belsito says. "This includes accurately identifying the irritant or allergen and taking preventive efforts."

He adds that most workers with occupational contact dermatitis who change jobs should do so for reasons other than dermatitis. A job change is only necessary in cases of severe allergy, where the agent causing the problem cannot be avoided.

While occupational contact dermatitis often can be managed successfully without having to leave a profession, that isn't always the case with occupational asthma.

"The outcome is related to whether an allergy or irritant is causing the asthma, and it depends on how long the person is exposed," says Bardana. "In general, if an allergy is causing the asthma, a person can't go back to the profession. The quicker they are removed from the agent they are allergic to, the better."

Greenberger adds, "It may be reasonable to go back to work if asthma is mild. But there are some workers that have loss of lung function, and this is a serious concern."

In cases where an irritant is causing asthma, worker education, appropriate ventilation, or the use of masks might allow someone to continue in a job.

Greenberger acknowledges the difficult choices people face when trying to hold on to a good-paying job while suffering with coughing, wheezing, and loss of breath, and it's not always clear whether occupational asthma is the driving factor.

"Some workers seek compensation with a belief that everything is caused by their work environment, even when it is not," Greenberger says. "But there are also workers with occupational asthma who refuse to stay off the job because they need to make a living. It's difficult. We want workers to keep their jobs, but we don't want them to lose their lung function."

In some cases, the loss of lung function associated with occupational asthma may be irreversible.

An allergist, an expert in the diagnosis and treatment of allergies and asthma, can perform allergy testing to identify the specific substances that trigger allergic reactions and determine the most appropriate and effective treatment.

The American College of Allergy, Asthma & Immunology is a professional medical organization based in Arlington Heights, Ill., that promotes excellence in the practice of the subspecialty of allergy and immunology. The organization, comprised of more than 5,000 allergists-immunologists and related health-care professionals, seeks to foster collaboration in which its members work together and with others to further patient care, education, advocacy, and research.