<unk>  is divided into different categories depending upon whether its cause can be determined or not. Known causes include certain medications or environmental triggers, parasitic infections, and cancer.<unk>  can also occur when the immune system attacks the lungs, a disease called<unk>  granulomatosis with polyangiitis. When a cause cannot be found, the<unk>  is termed "idiopathic". Idiopathic<unk>  can also be divided into acute and chronic forms, depending on the symptoms a person is experiencing.
Eosinophilic pneumonia
Atypical pneumonia
Acute eosinophilic pneumonia
Lipid pneumonia
Cryptogenic organizing pneumonia
Lobar pneumonia
Parasitic pneumonia
Fungal pneumonia