Update on irritant-induced occupational asthma

Abstract

Purpose of reviewIn this narrative review, we aim to highlight novel research findings on both acute/subacute irritant-induced asthma (IIA) and chronic exposure IIA (also called ‘low dose’ IIA).Recent findingsNovel case series showed that acute and subacute IIA cases had similar causal agents (e.g., acid or base aerosols/fumes, dusts, mixtures) but had occurred in different circumstances (accidents vs. regular work). Acute and subacute IIA cases had similar clinical characteristics but poorer short-term outcomes than sensitizer-induced occupational asthma patients. Novel large epidemiological studies reported associations between chronic occupational exposure to irritants and current adult-onset asthma and poor asthma control, and with a specific asthma endotype characterized by neutrophilic inflammation and oxidative stress. Recent studies reconfirmed the association of the use of disinfectants and cleaning products (especially sprays) with IIA. A role for genetic susceptibility has been suggested.SummaryRecent literature provided further understanding of both acute/subacute and chronic exposure IIA, in terms of causes, possible mechanisms, and consequences such as poor asthma control. Research is needed to clarify several aspects of IIA, including its frequency (still likely underestimated), modulating factors, and mechanisms. Research aiming at improving irritant exposure assessment, including intensity/duration, and determining relevant exposure windows would be welcome.

Occupational lung disease: when should I think of it and why is it important?

“…IIA can also develop after repeated symptomatic exposures to a high level of irritants (subacute or probable irritant-induced asthma) [ 9 ]. The symptoms experienced are the same as for acute IIA.…”

“…It may be more common than acute IIA but is likely under-recognised because the relationship between multiple exposures and the onset of symptoms is more difficult to establish [ 8 , 10 ]. Additionally, in epidemiological studies, chronic or repeated exposure to low-to-moderate levels of irritant substances had increased asthma risk (low-dose or possible irritant-induced asthma) [ 9 ]. It is not possible to diagnose this type of irritant-induced asthma with certainty at an individual level, because the association between exposure and the onset of asthma symptoms is difficult to establish [ 8 ].…”

The Saudi initiative for asthma – 2024 update: Guidelines for the diagnosis and management of asthma in adults and children

“…It is advisable to avoid going out in the storm, especially for those with uncontrolled asthma[ 77 ] Occupational exposures: Whenever an occupational sensitizer is identified, it is advisable to keep the affected person away from that environment. [ 78 ] The earlier the removal of this sensitizer takes place, the higher the chance of complete recovery from occupational asthma Food and drugs: Food and food additives are uncommon triggers of asthma. Avoidance is not generally recommended until it is documented by a specialist.…”

“…Occupational exposures: Whenever an occupational sensitizer is identified, it is advisable to keep the affected person away from that environment. [ 78 ] The earlier the removal of this sensitizer takes place, the higher the chance of complete recovery from occupational asthma…”

Chronic occupational exposures to irritants and asthma in the CONSTANCES cohort

“…Irritant-induced asthma can appear after a single acute exposure to very high levels of irritants (reactive airway dysfunction syndrome or Brooks' syndrome) but may also occur following a delayed onset after chronic exposures to irritants, even in the absence of high peak exposures. 7 The role of chronic exposures, whether in the past or currently, to irritants has been less documented 7 and is probably underestimated and involved in a substantial number of occupational asthma cases. 8 Because causality for chronic exposure irritant-induced asthma cannot be established with certainty at individual level (given the lack of appropriate clinical tests), epidemiological studies are particularly important to evaluate causality at population level.…”