Pneumopathies d’hypersensibilité domestiques. Alvéolites allergiques extrinsèques domestiques

Clinical Manifestations of Human Exposure to Fungi

Biological particles, along with inorganic gaseous and particulate pollutants, constitute an ever-present component of the atmosphere and surfaces. Among these particles are fungal species colonizing almost all ecosystems, including the human body. Although inoffensive to most people, fungi can be responsible for several health problems, such as allergic fungal diseases and fungal infections. Worldwide fungal disease incidence is increasing, with new emerging fungal diseases appearing yearly. Reasons for this increase are the expansion of life expectancy, the number of immunocompromised patients (immunosuppressive treatments for transplantation, autoimmune diseases, and immunodeficiency diseases), the number of uncontrolled underlying conditions (e.g., diabetes mellitus), and the misusage of medication (e.g., corticosteroids and broad-spectrum antibiotics). Managing fungal diseases is challenging; only four classes of antifungal drugs are available, resistance to these drugs is increasing, and no vaccines have been approved. The present work reviews the implications of fungal particles in human health from allergic diseases (i.e., allergic bronchopulmonary aspergillosis, severe asthma with fungal sensitization, thunderstorm asthma, allergic fungal rhinosinusitis, and occupational lung diseases) to infections (i.e., superficial, subcutaneous, and systemic infections). Topics such as the etiological agent, risk factors, clinical manifestations, diagnosis, and treatment will be revised to improve the knowledge of this growing health concern.

The association between fungi exposure and hypersensitivity pneumonitis: a systematic review

A systematic review of published studies focused on the association between hypersensitivity pneumonitis (HP) and fungi exposure was conducted on PubMed, following PRISMA guidelines for systematic reviews. A total of 14 studies met the inclusion criteria but only 6 of these studies were eligible, as the remaining 8 represented case reports that were separately included for further discussion. HP is an interstitial lung disease (ILD) characterized by a hypersensitization response to inhalable antigens and represents 1.5% to 12% of all ILD in the European population. Several fungi species that populate the indoor environment have been associated with the incidence of HP upon cumulative exposure, with Penicillium spp and Aspergillus spp being the fungi species most frequently associated with the onset of disease. Although some studies have shown that avoiding exposure to causative HP fungi tends to improve patients’ symptoms, other studies were unable to identify the source of sensitization. More microbial exposure studies are needed to properly estimate the risk of HP development in the built environment.

[Two cases of hot tub lung disease: Environmental investigations]

INTRODUCTION

Hot tub lung is a hypersensitivity pneumonitis (HP) due to exposure to inhaled non-tuberculous mycobacteria, the most frequent being Mycobacterium avium complex (MAC).

CASE REPORT

A French couple developed typicalHP in the context of a repeated use of hot tubs. The husband had a severe hypoxemic form whereas his wife had a micronodular form with patchy ground glass on the thoracic scan, with less severe functional impairment. MAC was recovered in the hot tub water, but not in broncho-alveolar lavage fluid, and serologies were negative. Samples taken at home showed unusual exposure to Aureobasidium pullulans and Aspergillus flavus, as well as the presence of potentially responsible domestic molds. Blood precipitins for these microorganisms were identified. The evolution was favorable after removal of the hot tub.

CONCLUSIONS

These cases represent two of the typical presentations of hot tub lung, with a possible HP to an antigen other than MAC, which may have been enhanced by chronic exposure to multiple microorganisms.

Hypersensitivity pneumonitis: Antigen diversity and disease implications

Hypersensitivity pneumonitis (HP) is an immune-mediated syndrome triggered by inhalation of a wide variety of allergens, to which an individual has previously been sensitized. More than 200 agents responsible for the disease have already been identified; however, HP occurs only in a small number of individuals exposed to causal antigens. The present report provides an overview of the role of antigen role in HP, highlighting its diversity, research methods, and prevention strategies, as well as the impact on disease prognosis following elimination of antigen. HP is an underdiagnosed disease and, therefore, it is difficult to accurately estimate its incidence. Triggering antigens can be divided into six broad categories: bacteria, fungi, mycobacteria, animal and plant proteins, chemicals, and metals, represented by disease prototypes. The identification of causal antigen is a major challenge; it is impossible to obtain in about 30-60% of cases. The acute form of HP, with early detection and immediate eviction of causal antigen, tends to have an excellent prognosis. In the chronic form, partial recovery of disease is still possible; however, some cases tend to progress to fibrosis, even after removal from exposure. In conclusion, HP diagnosis should be based on a proactive search for potential antigen sources, although their identification is hampered by the lack of standardized methods of demonstrating the specific antigen sensitization. Antigen avoidance is a critical determinant in disease prognosis.

[Hot tub lung: A case report]

Hot tub lung is a type of hypersensitivity pneumonitis caused by inhalational exposure to the Mycobacterium avium complex. We report the case of a 14-year-old boy presenting dyspnea with hypoxemia, whose medical history and clinical course helped make the diagnosis. Infectious causes were considered first, and antibiotics were initiated without success. Further questioning and explorations led to discussing a hypersensitivity pneumonitis diagnosis. Relapse after exposure to a hot tub enabled us to confirm hot tub lung. Hypersensitivity pneumonitis is a rare cause of pulmonary disorder, especially in children. It should be discussed with unusually severe and progressive cough or dyspnea. Further explorations should therefore be undertaken (CT, fibroscopy). Taking a precise medical history allows early diagnosis, leading to a quick withdrawal from the allergenic source and appropriate treatments.