Approach

The treatment of symptomatic asthma in a patient with occupational asthma (OA) should follow established guidelines for the pharmacological management of asthma, such as the Global Initiative for Asthma (GINA) guidelines, along with the recommendation to avoid further exposure to the causative agent.​[22]​​[36]​​​​[52][57]​​​​[71]​​​[89]​

If the patient remains at the workplace, strategies to avoid exposure include elimination or substitution of the causative agent, or relocation away from the area of exposure.

Patients with severe symptoms may require treatment in an emergency department and/or hospital admission, with treatment as for acute asthma.[57] This should be followed up with management as per guidelines for chronic asthma symptoms. The GINA guidelines recommend a stepwise approach, whereby medication is stepped up or stepped down based on disease severity and adequacy of asthma control.[57] See Acute asthma exacerbation in adults and Asthma in adults.

A workers' compensation claim should be initiated for patients with OA. Workers with OA may suffer significant socioeconomic consequences despite compensation programmes.[90]​ These consequences may limit the patient's ability to avoid further exposure to a sensitising agent or irritant if a change of employment is required.[91]​​[92]​​

Sensitiser-induced OA: removal from exposure

Early diagnosis of sensitiser-induced OA and avoidance of further exposure to the causative agent offers the best chance of recovery.[22]​​[36]​​[71]​​​​​​[90]​​​[93]

Very low-quality evidence suggests that 4 years after removal from exposure to the causal agent, the likelihood of reporting absence from asthma symptoms, or improvement in asthma symptoms, increases significantly compared with continued exposure (risk ratio 4.80 and 2.47, respectively).[90]​ Approximately 25% to 30% of OA patients removed from exposure can expect to make a full recovery; an additional 30% to 35% will report a reduction in symptoms.​[90][22]​​​ Much of the improvement occurs within the first 2 years following cessation of exposure.[22]​ ​Removal from exposure (but not reduction of exposure) may improve lung function compared with continued exposure.[90]​​

The likelihood of improvement or resolution of symptoms is greater in those workers who have relatively normal lung function, and shorter duration of symptoms, at the time of diagnosis.[22]​​[94]​​​​​​

In addition to removal from the exposure, early treatment with inhaled corticosteroids may be of benefit.[36][95]​​[96] However, pharmacological treatment is ineffective in preventing lung function deterioration if the worker remains exposed to the causative agent.

Reduction in exposure level is ineffective

As there is no clear safe level of exposure for sensitised workers, neither the reduction of the level of exposure nor the use of respiratory protection is recommended as an effective control measure.[36][71]

Patients with OA who have ongoing exposure will generally deteriorate, and fatal cases of OA have been reported with exposure to the causative agent.[22]​​[31][36]​​​​​​[71][97]​​​​

Irritant-induced OA

Patients may be able to return to the same workplace if the chance of an exposure similar to that which initiated asthma is considered unlikely, and if protective measures are in place at work.

Work modifications for the patient will depend on the severity of ongoing asthma and the work exposure conditions. Low irritant exposures at work may cause exacerbations, and preventive measures may be needed to further reduce exposures (such as use of a respirator at times or a move to a cleaner area).[36]

Patients should be medically monitored for symptoms, reliever inhaler requirements, and lung function (peak flow readings) when they return to work. Those who develop severe asthma or work in areas with significant potential asthma triggers may require modified work or change of employment

Non-occupational exposure control and patient education

As for other patients with asthma, exposure to non-occupational relevant asthma triggers should be controlled, such as exposure to relevant common allergens and irritant agents.

Patient education as to appropriate exposure control measures, use of drugs, and recognition of poor control is essential.[57][58][59]

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