Japanese farmer hospitalised after repeated exposure to black mould on onion peels

An onion farmer in Japan was hospitalised after developing a rare allergic reaction from repeated exposure to mouldy peels, according to a report published in the journal Respiratory Medicine Case Reports.

The 62-year-old man had worked as an onion farmer for several years before developing shortness of breath, fatigue and a dry cough. After experiencing the symptoms for two weeks, he was admitted to the hospital.

Lab tests and a CT scan showed high levels of inflammation in the lungs caused by the mould Aspergillus niger. He was diagnosed with hypersensitivity pneumonitis by Dr Akira Yamasaki, a respiratory medicine specialist from Tottori University Faculty of Medicine in Japan.

According to the National Heart, Lung and Blood Institute (NHLB), hypersensitivity pneumonitis triggers an immune response and causes air sacs in the lungs to become inflamed. These air sacs, known as alveoli, stretch and relax with each breath. But when inflamed, they lose their flexibility and develop scar tissue over time, making breathing difficult.

The farmer usually wore a mask while he worked, but had stopped doing so when his shortness of breath and cough started, said Dr Yamasaki. Without a mask, he was repeatedly breathing in the black mould on the onion peels.

The man had been a smoker for 35 years. To confirm if mould was indeed the cause of his hypersensitivity pneumonitis, and not his smoking, the farmer was asked to return home after his symptoms eased, and monitor his condition for three days.

On the second day home, he went back to work and cleaned the onion peels with an air compressor. Three hours into the task, he developed a low-grade fever. When he returned to the hospital the next day, he had also developed a cough.

Doctors repeated the three-day provocation test but told the farmer not to clean up any onion peels. This time, he did not develop any symptoms.

It was concluded that the man’s lung problems were indeed caused by Aspergillus niger and he was advised to wear a thick, filtering mask when working.

Dr Yamasaki said the man has since fully recovered, with no residual lung problems.

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