Inflammation

Inflammation is the body’s response to injury, which may be acute or chronic. Acute inflammation is the immediate defensive reaction of tissue to any injury, which may be caused by infection, chemicals or physical agents and involves pain, heat, redness and swelling (Martin and McFerran, 2008). It has also been defined as a set of local cellular and vascular responses to tissue damage or infection, which accelerates the destruction and phagocytic removal of invading organisms and debris (McGeown, 2002). The fundamental inflammatory process occurs in many dermatological conditions, where there is the key indicator of redness or erythema over the area due to blood flow.

Inflammation has a protective function by helping to eliminate the cause of tissue damage, removing dead cells and maintaining stability within the internal physiological environment. In the case of a wound there may be also swelling; heat, pain and loss of function, with injury leading to vasoconstriction of vessels at the margins of the wound. Hyperaemia then occurs in which the blood vessels within the area dilate, increasing local blood flow and redness. The damaged cells release chemical mediators such as bradykinin, histamine and serotonin, which increase capillary permeability, allowing the leakage of fluid into the tissues, causing oedema and possibly pain. The loss of plasma proteins exerts an osmotic effect in the tissues slowing down the flow of blood in the dilated vessels. As part of the protective response, white blood cells, particularly neutrophils, migrate from the vessels to the inflamed area attracted by the chemicals released by injured tissue cells and microorganisms. Antibodies within the exudate trigger neutrophils and macrophages phagocytosing these cells. Eventually fibrin builds up, with the inflamed area becoming sealed by the network of fibrin threads, localising the damaged tissues (McGeown, 2002; Hinchliff et al., 2005).

Inflammation is a common pathological process within dermatological disease. This is evident in many of the lesions and rashes, as outlined in Assessment and planning care. The inflammatory dermatoses include common skin disease such as psoriasis and eczema; these are illustrated within Psoriasis and Eczema.