* Pulmonary infection by bacteria, viruses and parasites * Drugs: antineoplastic drugs, erlotinib, amiodarone * Chemical exposure, most notably to diacetyl * Vaping: On October 17, 2019, the American Journal of Clinical Pathology reported that lung biopsies from patients with vaping-associated pulmonary illness show acute lung injury patterns, including<unk>  pneumonia. * Ionizing radiations * Inflammatory diseases * Systemic lupus * Rheumatoid arthritis (RA-associated<unk>  * Scleroderma * Bronchial obstruction * Proximal bronchial squamous cell carcinoma *SARS-CoV-2 *Analysis of COVID-19 CT imaging along with postmortem lung biopsies and autopsies suggest that the majority of patients with COVID-19 pulmonary involvement also have secondary<unk>  pneumonia (OP) or its histological variant, acute fibrinous and<unk>  pneumonia, which are both well-known complications of viral infections. It was identified in 1985, although its symptoms had been noted before but not recognised as a separate lung disease. The risk of<unk>  is higher for people with inflammatory diseases like lupus, dermatomyositis, rheumatoid arthritis, and scleroderma.
Cryptogenic organizing pneumonia
Acute eosinophilic pneumonia
Atypical pneumonia
Allergic bronchopulmonary aspergillosis
Chronic pulmonary aspergillosis
Eosinophilic pneumonia
Parasitic pneumonia
Fungal pneumonia