Coughing rust-colored sputum is mainly caused by Streptococcus pneumoniae, an acute inflammatory disease that involves most or all of the large lobes of the lung and is dominated by diffuse fibrinous exudation in the alveoli. In addition to Streptococcus pneumoniae, S. pneumoniae, Staphylococcus aureus, Streptococcus haemolyticus, and Haemophilus influenzae can also cause lobar pneumonia. The diagnosis can be made in the clinic based on symptoms and examination. The details are as follows. 1. There are often triggers such as cold, rain, fatigue or upper respiratory tract infection: the onset is rapid, with chills, high fever, chest pain, cough, mucopurulent sputum, bloody sputum or rust-colored sputum. Those with extensive lesions have shortness of breath and cyanosis, and some patients have gastrointestinal symptoms. 2.At present, early or atypical cases are common, and chest signs are mostly inconspicuous: typical cases have turbid percussion, fibrillation, voice enhancement, bronchial breath sounds and wet rales. Blood count and sputum culture: blood leukocyte count and neutrophil count are obviously increased, but the count may not be higher in severe infection or in old and weak people, but the neutrophil ratio is still increased. Sputum smear and sputum culture can find Streptococcus pneumoniae. 4, chest X-ray: X-ray examination early as a uniform faint shadow, large lobe solid into a large uniform dense shadow, mostly in the lobe, segmental distribution.