# Occupational asthma following single exposure to polyurethane foam containing methylene diphenyl diisocyanate – A case report

## TL;DR

A man developed severe asthma after a single exposure to polyurethane foam containing methylene diphenyl diisocyanate, highlighting the risks of such chemicals in the workplace.

## Contribution

This case report shows that a single high exposure to diisocyanates can cause occupational asthma without prior sensitization.

## Key findings

- Severe obstructive airway symptoms developed after a single high exposure to methylene diphenyl diisocyanate.
- Occupational asthma was confirmed through peak expiratory flow variability and a positive metacholine challenge.
- Preventive measures are crucial in workplaces where diisocyanates are used.

## Abstract

Diisocyanates are a group of chemicals used in many different applications, such as plastics, foams, coatings, adhesives, and sealants. Prolonged occupational exposure can result in severe asthma. This case report presents a non-smoking male without any previous respiratory disease, where severe obstructive airway symptoms developed during a single event with high airborne exposure to polyurethane foam containing methylene diphenyl diisocyanate during the coating of a large vehicle. The subject was subsequently diagnosed with occupational asthma based on a significant variability in a two-week peak expiratory flow curve and a positive metacholine challenge. Despite aborted exposure and optimized asthma treatment, the subject continued to experience debilitating airway symptoms. This case report demonstrates that severe asthma can develop following a single exposure to polyurethane foam containing methylene diphenyl diisocyanate, underscoring the importance of preventive measures in workplaces where such chemicals are used.

•Occupational exposure to diisocyanates can lead to asthma development.•One-time exposure without previous sensitization can be enough to cause asthma.•The diagnosis of diisocyanate asthma should ideally be based on a provocation test.

Occupational exposure to diisocyanates can lead to asthma development.

One-time exposure without previous sensitization can be enough to cause asthma.

The diagnosis of diisocyanate asthma should ideally be based on a provocation test.