Topic overview

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Unlike acute inflammation, which is dominated by neutrophils, chronic inflammation is characterized by macrophages, lymphocytes, and plasma cells. It may follow persistent infection, autoimmunity, prolonged exposure to toxic agents, foreign bodies, or metabolic conditions such as obesity. Interactions among immune cells and mediators sustain the response, while tissue destruction occurs alongside repair. Typical structural changes include a mononuclear infiltrate, parenchymal damage, fibrosis, and angiogenesis. Over time, scarring may impair organ function, and persistent inflammatory injury can contribute to selected cancers and systemic effects, including anemia of chronic disease, secondary AA amyloidosis, and cachexia. The full lesson develops these causes, mechanisms, morphologic features, and consequences in greater detail.