Chronic inflammation is a prolonged inflammatory response whereby inflammation, injury and repair coexist. It commonly occurs over a period of weeks to months and can follow an acute inflammatory response or begin independently in a slow, insidious manner.
Etiology
- prolonged infection
- prolonged exposure to toxic agents
- prolonged or recurrent trauma
- chronic ischemia
- hypersensitivity reactions
- foreign bodies
- autoimmune disease
Features
In contrast to acute inflammation, which is more of a stepwise response, chronic inflammation is characterized by three coexisting events:
- infiltration by mononuclear cells (macrophages, lymphocytes, plasma cells),
- prolonged tissues damage, likely caused by both the initial offending agent and the inflammatory response itself, and,
- attempted healing and repair.
Consequences
Chronic inflammation can be maladaptive as the prolonged inflammatory response can predispose to further tissue damage and even malignant transformation in some circumstances (e.g. marjolin ulcer) 3.