What is purulent sputum indicative of?

Purulent sputum is characterized by its thick, often yellow or green coloration, and it is typically indicative of a bacterial infection. The presence of pus in the sputum results from the immune response to bacterial pathogens, which leads to the accumulation of dead white blood cells and debris. This can typically be seen in conditions such as pneumonia, bronchitis, or lung abscesses, where bacteria are the primary causative agents.

In contrast, allergic reactions primarily produce clear, thin mucus, while asthma attacks may result in wheezing and increased mucus production without the purulent characteristics. Viral infections can also cause changes in sputum but generally do not lead to the thick, colored sputum associated with bacterial infections. Hence, when purulent sputum is observed, it strongly suggests the need for further evaluation and possibly antibiotic treatment focused on a bacterial cause.