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Year : 2022  |  Volume : 68  |  Issue : 4  |  Page : 243-244  

Hypersensitivity pneumonitis associated with mushroom cultivation

H Satoh1, H Yamada2,  
1 Division of Respiratory Medicine, Mito Medical Center, University of Tsukuba, Mito, Japan
2 Division of Respiratory Medicine, Hitachinaka Medical Center, University of Tsukuba, Hitachinaka, Japan

Correspondence Address:
H Satoh
Division of Respiratory Medicine, Mito Medical Center, University of Tsukuba, Mito

How to cite this article:
Satoh H, Yamada H. Hypersensitivity pneumonitis associated with mushroom cultivation.J Postgrad Med 2022;68:243-244

How to cite this URL:
Satoh H, Yamada H. Hypersensitivity pneumonitis associated with mushroom cultivation. J Postgrad Med [serial online] 2022 [cited 2023 Sep 28 ];68:243-244
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For workers dealing with organic substances as well as chemicals, hypersensitivity pneumonitis is an important occupational lung disease.[1],[2] It involves an immunoallergic mechanism caused by chronic inhalation of antigens and has significant morbidity, and early diagnosis and removal from exposure to the antigen are critically important in its management.[1],[2]

A 50-year-old woman with a 3-month history of persistent dry cough and shortness of breath was admitted to our hospital. The patient was involved in mushroom, abalone mushrooms (Pleurotus eryngii var. tuoliensis) and shimeji mushrooms (Hypsizygus marmoreus), cultivation for 6 years. Bilateral fine crackles were audible in the base of both lungs. The arterial oxygen saturation was 94% in room air. On admission, her white blood cell count was 5800/μL, and C-reactive protein was 1.62 mg/dL. A chest CT scan revealed mosaic attenuation in both lung fields [Figure 1]a. Hence, a provisonal diagnosis of pneumocystis pneumonia was considered. Beta-d glucan testing was done, but it was 16.3 pg/mL, within the normal range. The bronchoalveolar lavage fluid showed lymphocytosis (90%) and a low cluster of differentiation (CD) 4/8 ratio (1.14). The specimens obtained by transbronchial lung biopsy revealed alveolitis. The patient was advised rest at home for 2 weeks. The symptoms improved and the mosaic attenuation on the CT image also improved [Figure 1]b. Based on these findings and clinical course, the patient was diagnosed with hypersensitivity pneumonitis associated with mushroom cultivation.{Figure 1}

Hypersensitivity pneumonitis is caused by repeated inhalation of organic or inorganic dust such as fungal spores, bacteria, and animal proteins. During indoor cultivation of mushrooms, a large number of spores, 4–8 μm in size, are suspended in the air. Some of the mushroom cultivators are sensitized by repeated inhalation of high concentrations of mushroom spores, and hypersensitivity pneumonitis develops by the mechanism of type III and type IV hypersensitivity. Hypersensitivity pneumonitis is also known as mushroom workers' lung, and thermophilic actinomycetes that grow in the compost are thought to cause this condition.[3],[4],[5]

Noster et al. in 1975[6] were the first to report hypersensitivity pneumonitis caused by the inhalation of edible mushroom spores called oyster mushrooms.[6] In recent years, there have been reports of various types of mushroom workers' lung such as shimeji mushrooms, king trumpet mushrooms, and nameko mushrooms, all of which are attributed to the mushroom spores or the mushrooms themselves.[3] In a diagnosis, it is necessary to listen to the medical history in detail, keeping in mind the causative antigen. It is important to confirm that exacerbation of symptoms occurs after work related to mushroom cultivation. In some cases, it may be necessary to do antigen testing to confirm the diagnosis. According to the American Thoracic Society Guideline, ground-glass opacities, poorly defined centrilobular nodules, and mosaic attenuation on inspiratory CT images, and air trapping on expiratory CT images are typical paterrns of non-fibrotic hypersensitivity pneumonitis.. Pulmonary function testing and sedimentation antibody test against the offending antigen can help provide useful information for diagnosing the condition. The treatment is based on the avoidance of identified antigens. In some patients, steroids and immunosuppressive drugs may be used to control the allergic inflammation and prevent lung fibrosis.

In today's word mushroom cultivation is increasing. Workers involved in the cultivation and distribution of edible mushrooms are at risk of developing hypersensitivity pneumonitis. Although still rare, medical professionals need to consider this diagnosis when examining a patient with persistent respiratory symptoms.

Declaration of patient consent

The authors certify that appropriate patient consent was obtained.

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