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“I had no clue that things I alwaysthought were safe and inert couldcause asthma,” says Stephens, now33. He worked in a bakery to helpmake ends meet while attending theUniversity of Oklahoma during themid-1990s. “I had never even heardof someone going to work and com-ing home with asthma.”

11 Million at RiskIn December 2003, scientists from

the University of Birmingham in

England released the results of a sur-vey, which found that bakers, timberworkers, dentists, and waitresses arethe workers reporting the highestrates of adult-onset asthma. The sur-vey results also indicate the peoplemost likely to develop occupationalasthma are those with a personal orfamily history of allergies or asthmaand frequent exposure to highly sen-sitizing substances. However, somepeople, such as Stephens, have nofamily history of asthma or allergy.

“I felt fine when I began workingat the bakery, but after a couple ofmonths I noticed that I would startto wheeze and have difficulty breath-ing when I made bread,” saysStephens, who is now a graphicdesigner in Minneapolis. “The lagtime really made it difficult to pin-point the cause of the problem.”Today, Stephens still needs medica-tion to control his asthma.

Occupational asthma is the mostcommon work-related lung disease in

Gregory Alford

It took almost a year for George Stephens to learn that hisasthma was caused by the white haze floating through thebakery where he worked. Stephens knew he was breathingsmall particles of flour and other dry ingredients, but he hadno idea it was making him sick.

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many industrialized countries.Although estimates vary, it is thoughtthat 15% of adult-onset asthma casesin the United States may be attribut-able to workplace exposures. TheOccupational Safety and HealthAdministration (OSHA) estimates11 million workers in the UnitedStates are exposed to at least one ofthe almost 400 substances known tobe associated with occupational asth-ma. (See sidebar for list of commonhazardous substances.)

Types of OccupationalAsthma

Kenneth D. Rosenmann, MD,professor of medicine at MichiganState University, has studied work-place asthma (the term he prefers)for more than 15 years. He says

occupational asthma generally takesone of 3 forms.• Sensitizing asthma: This is the

type with which Stephens wasdiagnosed. It tends to developslowly after repeated exposure.This allergy-related asthma is themost commonly diagnosed formof occupational asthma.

• Preexisting Occupational Asthma:This type involves a preexistingasthma condition that is signifi-cantly aggravated after exposure toan irritating substance in theworkplace.

• Reactive Airway DysfunctionSyndrome (RADS): This thirdtype of occupational asthma canoccur after one or more exposuresto high levels of airway irritants.(Common irritants that may causethis are hydrochloric acid, chlo-rine, acetic acid, and ammoniafumes, according to DrRosenmann.) Initial symptomsmay include shortness of breath,wheezing, cough, and respiratorydistress. Although the initialsymptoms usually improve, even asingle exposure can result in long-term reactive airway dysfunction.According to Dr Rosenmann,

there is a common pattern of occupa-tional asthma. “Symptoms of work-place asthma include wheezing, chest

tightness, coughing, and shortness ofbreath. Symptoms usually occur whilethe worker is exposed to a particularsubstance at work. In some cases,symptoms may not develop untilseveral hours after work.” He addsthat in the early stages of the disease,symptoms usually decrease or disap-pear during weekends or vacations,only to flair up after returning towork. In later stages of the disease,common substances such as cigarettesmoke, dust, or cold air may triggerasthma symptoms.

In rare cases, occupational asthmacan prove fatal. “I recently becameaware of a workplace-related asthmadeath in Michigan,” says Dr.Rosenmann. “A man in his mid-40swho managed a mom-and-pop autodetailing shop collapsed and died atan urgent care clinic after spraying achemical bed liner. The man wasexposed to isocyanates, which areused to produce polyurethane poly-mers. Isocyanates are a commoncause of workplace asthma andRADS.” Michigan OSHA cited thecompany for 7 workplace safety vio-lations after the death.

In the Michigan case, previouswork-related asthma attacks hadbeen treated only with albuterol anda short course of oral corticosteroids,which rankles Dr. Rosenmann. Hebelieves too few physicians aggres-sively diagnose and adequately treatoccupational asthma. People whosuspect the workplace is causing orcontributing to their asthma shoulddiscuss the issue with their doctor.Ask for a referral or switch healthcare providers if the topic is unfamil-iar to your physician, he advises.

Diagnosis and TreatmentAllergists, immunologists, pulmo-

nologists, and occupational medicinespecialists are generally those withthe most experience diagnosing andtreating occupational asthma. Whenoccupational asthma is suspected,thorough medical and work historiesare taken, and a complete physicalexamination is performed. The fre-

Common SubstancesAssociated WithWorkplace Asthma

Organic Chemical Mineraldusts dusts dusts

Flour Vapors PlatinumCereals Plastics ChromiumGrains Paints CottonWood Epoxies Nickel sulfateCoffee InsulationTeaFlax

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quency, duration, and severity ofsymptoms are also noted.

Laboratory tests of blood and spu-tum may help confirm the presenceof specific irritants and assist in diag-nosing occupational asthma. It takescommitment on the part of bothphysician and patient to properlydiagnose occupational asthma, saysDr. Rosenmann. “It can be difficultto diagnose. I ask patients keep adiary of their peak flow readings,taking one [reading] every 2 hours.It’s also important to have spirometrytests performed on a regular basis.[This is done at your doctor’s office.]Another key is to have spirometryreadings done over a period of time,usually 2 weeks, while the patient isaway from the workplace,” he says.

An important aspect of treatmentfor occupational asthma is simply toavoid the substance causing the asth-ma. Employers sometimes provideaffected workers with a different job,or allow the person to do their job ina different location within the facility(away from the offending substance)when possible. Other steps employ-ers may take are to improve ventila-tion, provide personal protective

equipment, or educatestaff members.However, when con-tinued exposure atwork is unavoidable,even if it is only inter-mittent, the personmay have to leave thejob. In addition toavoidance, aggressivedrug treatment andregular monitoringare usually recom-mended. Many peoplerequire life-long treat-ment to control theiroccupational asthma,even after they are nolonger exposed to theharmful substance.

Dr. Rosenmannnotes that an accuratediagnosis of occupa-tional asthma impacts

more than treatment decisions.Severe cases may qualify for workers’compensation benefits. The numberof people filing claims is on the rise.Between 1994 and 1998, theWashington State Workers’Compensation Fund claims rate forwork-related asthma increased by70%.

Career VersesHealth

Although Stephensfound it fairly easy toleave his job as abaker, some peoplehave much more dif-ficulty when forcedto leave an estab-lished career due tohealth concerns.Shelly Newman, 41,of Dallas, Tex.,changed careers afterbeing diagnosed withsensitizing occupa-tional asthma in1999. As a registerednurse who had prac-ticed for more than10 years, Newman

routinely wore latex gloves. Afterseveral years and thousands of expo-sures, she developed an allergy tothe latex protein. She eventuallybecame so sensitive that she couldnot touch or be near products thatcontained latex (which are commonin hospitals) without triggeringallergy and asthma symptoms.

“I loved working at the bedsidebut couldn’t handle the wheezingand sneezing after a while,” explainsNewman. After much deliberation,she went back to college andbecame a teacher. “My family and Ihad to make sacrifices. In the end, Irealized that life isn’t perfect andbeing healthy is more importantthan any job.”

For more information about occu-pations and substances that can causeoccupational asthma, visit the Asmaproweb site at www.asmanet.com/asmapro/agents.htm

Susan Berg is a freelance writer inSharon, Mass., who writes abouthealth care and consumer issues.

Reprint orders: Elsevier Inc., 11830 WestlineIndustrial Dr., St. Louis, MO 63146-3318;phone (314)453-4350.doi: 1016/j.asthmamag.2004.01.003