humidifier fever

Humidifier fever is an influenza-like illness caused by exposure to molds growing in humidifier systems. It is a form of hypersensitivity pneumonitis, where the lungs become sensitized to various agents. Symptoms include fever, headache, and muscle pain, and it can sometimes present as a nonbacterial pneumonia.1

Legionnaire disease is a more severe form of pneumonia caused by Legionella pneumophila bacteria, often found in contaminated water systems, including air-conditioning units. Symptoms include fever, chills, cough, and shortness of breath. While humidifier fever is an allergic response, Legionnaire disease is a bacterial infection. Both can cause fever and respiratory symptoms, but they have different causes and treatments.21