**1. Introduction**

In assessing the role of inflammation in burn injuries, it is important to first recognise differences in the pathophysiology of burns. Unlike other wounds, burns consist of three zones of injury, initially described by Jackson in the British Journal of Surgery in 1953. These are the zone of coagulation, the zone of stasis and the zone of hyperaemia [1] (**Figure 1**).

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**2. Inflammation and the healing cascade**

which may arise following burn injury.

**Figure 2.** Schematic diagram of the three phases of the healing cascade.

Burn injuries initially present with local swelling (oedema) and redness (erythema) around the site of injury (**Figure 1**). More severe, second or third degree burns, which affect more than the superficial epidermis, are characterised by greater levels of oedema and erythema, alongside the formation of blisters and inflammation [2]. This inflammation is indicative of the active immune response which is an integral part of the wound healing cascade, however, it can be significantly elevated in severe burn patients [5, 8]. Although the source of the injury may differ, the phases of wound healing are generally similar and can be described as phases of haemostasis and inflammation, proliferation and remodelling [9] (**Figure 2**). These interrelated and overlapping phases normally progress over a matter of days or weeks to effectively heal a wound, although the timings are often different between types of wounds [10]. In acute wounds, the inflammatory phase lasts for the first 5–7 days, however, severe burns may display chronic, persistent inflammation long after the initial tissue damage and may even result in multiple organ failure (MOF) due to systemic inflammatory response syndrome (SIRS) [11, 12]. Moreover, dysregulation of the inflammatory response and the subsequent progression through the phases of healing are associated with sub-optimal wound outcomes and excessive inflammation can lead to large, thick and restrictive scars [13, 14]. Thus, understanding the interaction between the early inflammatory phase and the later proliferative and remodelling phases of healing are important for understanding the particular complications

The Role of the Inflammatory Response in Burn Injury http://dx.doi.org/10.5772/intechopen.71330 39

**Figure 1.** Scald burn in a child showing the Jackson's three zones of damage. (a) Zone of coagulation, (b) zone of stasis and (c) zone of hyperemia. Reproduced from [2].

The primary site of injury, classified as the zone of coagulation, is the site of the most damage and will rapidly undergo necrosis. Outside of this zone, is the zone of stasis that is characterised by reduced blood flow or ischemia and further out, the zone of hyperaemia where microvasculature is not damaged but displays increased blood flow and significant inflammation [2]. If inflammation and vascularisation are not quickly returned to normal, the zone of stasis may also undergo necrosis meaning that the size of the wound may in fact enlarge over time [3]. Thus, the direction of injury in burns is predominantly horizontal as opposed to the vertical injury of an incisional wound [4]. Whilst burn injuries differ from other wound types in that they are sterile at the time of injury, rapid blistering and necrosis of the injured tissue soon opens the wound up to pathogens and the risk of infection [2]. Burns wounds are often larger than other types of wounds, particularly those arising from scalds or exposure to flame and burn injuries covering greater than 20% of the total body area can quickly lead to burn shock due to widespread oedema and fluid loss [5]. The immune status of the patient is also altered following severe burn injuries further contributing to the risk of infection [6]. Thus, infections can quickly overcome a patient if not effectively controlled. It may be for this reason that the inflammatory response in burns is so intense. Moreover, the activity of the immune cells is often dictated by the specific signals encountered within the microenvironment at the site of inflammation or injury [7]. So understanding the factors which alter the protein pathways which are altered in burn wounds is pivotal in the development of therapies to restore balance to the immune response in burn patients and support effective healing of the wound.
