Principal Reccomendations

Employers, health and safety personnel and health practitioners should be aware that at least 1 in 10 cases of new or recurrent asthma in adult life are attributable to occupation.			***	A
***	2++	Occupational factors are estimated to account for 9-15% of cases of asthma in adults of working age, including new onset or recurrent disease.

Employers and their health and safety personnel should be aware of the very large number of agents known to cause occupational asthma and the risk of exposure to such agents.			**	B
***	2++	The most frequently reported agents include isocyanates, flour and grain dust, colophony and fluxes, latex, animals, aldehydes and wood dust.

Employers and their health and safety personnel should be aware that the major determinant of risk for the development of occupational asthma is the level of exposure to its causes.			**	B
***	2++	The risk of sensitisation and occupational asthma is increased by higher exposures to many workplace agents.

Health practitioners should not use poorly discriminating factors - such as atopy, family or personal history of asthma, cigarette smoking and HLA phenotype - which increase individual susceptibility to exposure as a reason to exclude individuals from employment.			*	D
*	3	The positive predictive values of screening criteria are too poorly discriminating for screening out potentially susceptible individuals, particularly in the case of atopy where the trait is highly prevalent.
*	3	A previous history of asthma is not significantly associated with occupational asthma.

Employers should implement programmes to prevent (i.e. reduce the incidence) of occupational asthma by removing or reducing exposure to its causes through elimination or substitution and where this is not possible, by effective control of exposure.			**	B
***	2++	The risk of sensitisation and occupational asthma is increased by higher exposures to many workplace agents.
***	2++	Reducing airborne exposure reduces the number of workers who become sensitised and who develop occupational asthma.
*	3	The use of respiratory protective equipment reduces the incidence of, but does not completely prevent, occupational asthma.

Employers and their health and safety personnel should ensure that when respiratory protective equipment is worn, the appropriate type is used and maintained, fit testing is performed and workers understand how to wear, remove and replace their respiratory protective equipment.			*	D
*	3	The use of respiratory protective equipment reduces the incidence of, but does not completely prevent, occupational asthma.

Employers and their health and safety personnel should inform workers about any causes of occupational asthma in the workplace and the need to report any relevant symptoms as soon as they develop.			**	D
**	2+	The likelihood of improvement or resolution of symptoms or of preventing deterioration is greater in workers who have relatively normal lung function at the time of diagnosis.
**	2+	The likelihood of improvement or resolution of symptoms or of preventing deterioration is greater in workers who have shorter duration of symptoms prior to diagnosis.

Employers and their health and safety personnel should be aware that for most causes the risk of developing occupational asthma is greatest during the early years of exposure.			**	C
**	2+	Sensitisation and occupational asthma are most likely to develop in the first years of exposure for workers exposed to enzymes, complex platinum salts, isocyanates and laboratory animal allergens.

Employers and their health and safety personnel should provide regular health surveillance to workers where a risk of occupational asthma is identified. Surveillance should include a respiratory questionnaire enquiring about work-related upper and lower respiratory symptoms, with additional functional and immunological tests, where appropriate.			**	C
*	3	Health surveillance can detect occupational asthma at an earlier stage of disease and outcome is improved in workers who are included in a health surveillance programme.
**	2+	The likelihood of improvement or resolution of symptoms or of preventing deterioration is greater in workers who have relatively normal lung function at the time of diagnosis.
**	2+	The likelihood of improvement or resolution of symptoms or of preventing deterioration is greater in workers who have shorter duration of symptoms prior to diagnosis.

Health practitioners should provide workers at risk of occupational asthma with health surveillance at least annually and more frequently in the first two years of exposure.			**	C
**	2+	Sensitisation and occupational asthma are most likely to develop in the first years of exposure for workers exposed to enzymes, complex platinum salts, isocyanates and laboratory animal allergens.

Health practitioners should provide more frequent health surveillance to workers who develop rhinitis when working with agents known to cause occupational asthma and ensure that the workplace and working practices are investigated to identify potential causes and implement corrective actions.			**	C
**	2+	Occupational rhinitis and occupational asthma frequently occur as co-morbid conditions in IgE associated occupational asthma.
**	2+	Rhino-conjunctivitis is more likely to appear before the onset of IgE associated occupational asthma.
*	2-	The risk of developing occupational asthma is highest in the year after the onset of occupational rhinitis.

Health practitioners should provide more frequent health surveillance to any workers who have pre-existing asthma to detect any evidence of deterioration.
**	2+	Skin prick testing and blood sampling of exposed workers to conduct immunological tests is feasible in the workplace.

Health practitioners should consider the use of skin prick or serological tests as part of the health surveillance of workers exposed to agents that cause IgE associated occupational asthma to assess the effectiveness of the control of exposure and the risk of occupational asthma among workers.
***	2++	Occupational factors are estimated to account for 9-15% of cases of asthma in adults of working age, including new onset or recurrent disease.
***	2++	The most frequently reported agents include isocyanates, flour and grain dust, colophony and fluxes, latex, animals, aldehydes and wood dust.
***	2++	The workers most commonly reported to surveillance schemes of occupational asthma include paint sprayers, bakers and pastry makers, nurses, chemical workers, animal handlers, welders, food processing workers and timber workers.
**	2+	The workers reported from population studies to be at increased risk of developing asthma include bakers, food processors, forestry workers, chemical workers, plastics and rubber workers, metal workers, welders, textile workers, electrical and electronic production workers, storage workers, farm workers, waiters, cleaners, painters, plastic workers, dental workers and laboratory technicians.
**	2+	In the clinical setting questionnaires that identify symptoms of wheeze and/or shortness of breath which improve on days away from work or on holiday have a high sensitivity, but relatively low specificity for occupational asthma.

Health practitioners should enquire of any adult patient with new, recurrent or deteriorating symptoms of rhinitis or asthma about their job, the materials with which they work and whether their symptoms improve regularly when away from work.

***

A

Employers and their health and safety personnel should assess exposure in the workplace and enquire of relevant symptoms among the workforce when any one employee develops confirmed occupational rhinitis or occupational asthma and identify opportunities to institute remedial measures to protect other workers.
**	2+	The likelihood of improvement or resolution of symptoms or of preventing deterioration is greater in workers who have relatively normal lung function at the time of diagnosis.
**	2+	The likelihood of improvement or resolution of symptoms or of preventing deterioration is greater in workers who have shorter duration of symptoms prior to diagnosis.

Health practitioners should be aware that the prognosis of occupational asthma is improved by early identification and early avoidance of further exposure to its cause.

**

B

Health practitioners who suspect a worker of having occupational asthma should make an early referral to a physician with expertise in occupational asthma.

Health practitioners who suspect a worker of having occupational asthma should arrange for workers to perform serial peak flow measurements at least four times a day.			**	D
**	3	Acceptable peak flow series can be obtained in around two thirds of those in whom a diagnosis of occupational asthma is being considered.
*	3	The diagnostic performance of serial peak flow measurements falls when fewer than four readings a day are made.
**	3	There is high level of agreement between expert interpretations of serial peak flow records.
**	3	The sensitivity and specificity of serial peak flow measurements are high in the diagnosis of occupational asthma

Physicians should confirm a diagnosis of occupational asthma supported by objective criteria (functional, immunological, or both) and not on the basis of a compatible history alone because of the potential implications for future employment.			**	B
**	2+	In the clinical setting questionnaires that identify symptoms of wheeze and/or shortness of breath which improve on days away from work or on holiday have a high sensitivity, but relatively low specificity for occupational asthma.
*	3	Free histories taken by experts have high sensitivity, but their specificity may be lower.
**	2-	Approximately one third of workers with occupational asthma are unemployed up to 6 years after diagnosis.
**	2-	Workers with occupational asthma suffer financially.

Employers and their health and safety personnel should ensure that measures are taken to ensure that workers diagnosed as having of occupational asthma avoid further exposure to its cause in the workplace.			**	B
***	2++	The likelihood of improvement or resolution of symptoms or of preventing deterioration is greater in workers who have no further exposure to the causative agent.
**	2+	The likelihood of improvement or resolution of symptoms or of preventing deterioration is greater in workers who have shorter duration of symptoms prior to diagnosis.
*	3	Redeployment to a low exposure area may lead to improvement or resolution of symptoms or prevent deterioration in some workers, but is not always effective.

Physicians treating patients with occupational asthma should follow published clinical guidelines for the pharmacological management of patients with asthma in conjunction with recommendations to avoid exposure to the causative agent.
***	2++	The likelihood of improvement or resolution of symptoms or of preventing deterioration is greater in workers who have no further exposure to the causative agent.
**	2+	The likelihood of improvement or resolution of symptoms or of preventing deterioration is greater in workers who have shorter duration of symptoms prior to diagnosis.
*	3	Redeployment to a low exposure area may lead to improvement or resolution of symptoms or prevent deterioration in some workers, but is not always effective.

Health practitioners should enquire about pre-existing occupational asthma to agents that job applicants might be exposed to in their new job and advise affected applicants that they are not fit to undertake this work.

**

B