How do primary intention and secondary intention healing differ?

In medicine, the primary difference between primary and secondary intention healing lies in how the wound edges are managed and how the tissue repairs itself.12

• Primary Intention: This method is used for clean wounds where the edges can be brought together and closely opposed without tension. The wound is closed using sutures, skin adhesives, or tissue tapes. Because the edges are approximated, healing occurs with minimal tissue loss and typically results in less scarring.21

• Secondary Intention: This process is used when a wound is left open, often because it is infected or cannot be closed safely. The wound heals through the formation of granulation tissue (a combination of connective tissue and capillaries), wound contraction, and epithelialization, where new epithelium grows over the injury site. This process generally takes longer and may result in more significant scar formation compared to primary intention.12

A third category, known as delayed primary closure or third intention, involves leaving a potentially contaminated wound open for several days to minimize infection risk before it is surgically closed.12