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

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

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.

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.