What is the key feature of chronic inflammation?

Chronic inflammation is characterized primarily by its prolonged duration, distinguishing it from acute inflammation, which occurs suddenly and resolves quickly. This type of inflammation can last for months or even years, often resulting from ongoing irritants, such as persistent pathogens, autoimmune responses, or ongoing tissue damage.

The sustained nature of chronic inflammation leads to changes in the tissue architecture, which may result in fibrosis and scarring over time. This prolonged state often involves the continuous presence of inflammatory cells, such as macrophages and lymphocytes, and can result in a wide range of clinical outcomes, including the development of chronic diseases.

While rapid onset, short duration, and significant swelling are typically associated with acute inflammatory responses, they do not describe chronic inflammation accurately. In acute cases, inflammation occurs rapidly and resolves once the initial cause is removed, leading to a temporary swelling and influx of neutrophils. However, in chronic inflammation, the features are fundamentally different, focusing on a sustained response that is less about immediate swelling and more about long-term tissue changes.