Table 4.
Non-WRA | Sensitizer-induced OA |
---|---|
Asthma Severity | |
Greater severity in those with associated rhinitis | Greater severity in those with associated rhinitis |
Neutrophilic vs. eosinophilic airway inflammation associated with increased severity, worse lung function, less steroid responsiveness, but not related to nonspecific airway hyperresponsiveness. | Neutrophilic vs. eosinophilic airway inflammation associated with OA due to low-molecular-weight agents, in a noneosinophilic variant of OA and WEA, and with a poor prognosis. |
Overlap with Chronic Obstructive Pulmonary Disease | |
∼10% overlap with chronic obstructive pulmonary disease. | Overlap to be evaluated in epidemiological studies of occupational chronic obstructive pulmonary disease. |
Symptoms | |
Work-related wheeze, nose, eye itching, and lack of hoarseness are the most sensitive symptoms in cases of OA due to high-molecular-weight agents. | |
Diagnostic Tests | |
Mannitol less sensitive than methacholine for challenges. | Mannitol challenge may differentiate subjects according to severity of disease. |
FeNO is a surrogate marker of eosinophilic inflammation in asthma (rapid and less invasive). | FeNO may be useful in the interpretation of specific inhalation challenges in subjects who cannot produce satisfactory sputum samples. |
Assessment of mediators in induced sputum can show aspects of airway inflammation and remodeling. | |
Specific bronchial challenges are seldom used in non-WRA. | Specific bronchial challenges are reference tests for diagnosing OA, although not used in many centers. |
Definition of abbreviations: OA = occupational asthma; WRA = work-related asthma.
Similarities printed in bold. Features that differ or have only been only evaluated for one condition are not bold.
Irritant-induced asthma is not included here because these factors cannot be compared at present.