Wound healing can be affected by intrinsic, extrinsic, and iatrogenic factors. Intrinsic factors are related to the overall state of health of the patient, such as age, body type, chronic disease, immunosuppression, nutritional status, and hormonal levels. Extrinsic factors are related to the external environment and conditions of the wound, such as dehydration, blood supply, sepsis, and occlusive dressing. Iatrogenic factors are related to the medical interventions and treatments that can influence wound healing, such as medications, radiation therapy, and surgery. These factors can delay or complicate the wound-healing process by affecting cellular functions, immune response, and tissue repair.

Secondary wound healing occurs when the sides of the wound are not opposed, therefore healing must occur from the bottom of the wound upwards. It occurs in the same four stages as primary intention: Haemostasis, Inflammation, Proliferation, and Remodelling. In Haemostasis, a large fibrin mesh forms, which fills the wound. In Inflammation, an inflammatory response acts to remove any cell debris and pathogens present. In Proliferation, cytokines released by inflammatory cells drive the proliferation of fibroblasts and the formation of granulation tissue. Angiogenesis is promoted by the presence of growth mediators, allowing for further maturation of the granulation tissue; the production of collagen by fibroblasts allows for the closure of the wound after around a week. In Remodelling, collagen fibres are deposited within the wound to provide strength in the region, with the fibroblasts subsequently undergoing apoptosis.