Superficial skin wounds, such as abrasions or scratches, involving the epidermal layer, heal without resulting into scars. Deeper wounds, involving the dermis and subcutaneous layers (or hypodermis – see diagram below) results into scars.
There are 4 phases of healing: hemostasis (blood clotting); inflammation; proliferation (growth of new tissue) and maturation (remodelling).
Healing times vary from wounds to wounds, from different sizes and depths, from clean to dirty wounds, from patients to patients (with or without wound healing hindering factors). Complete healing (up to maturation) can range from one week to 2 years or more.
Ordinarily, when physicians advise patients on time of skin wound healing, they usually refer to the time when the wounds will be completely closed, dry, will not dehisce or open anymore and will not have complications like infection and bleeding. Again, the time of skin wound healing varies from wounds to wounds, different sizes and depths, from clean to dirty wounds, and from patients to patients. The healing time based on the above parameters can range from one to three weeks or even longer.
At one week – “healed” because wound is dry and with little risk for complications like infection and bleeding.
At 40 days, complete healing without any trace of injury (without scar).
One week after an operation (mastectomy) – “healed” because the wound is completely closed, dry, chances are will not dehisce or open anymore and will most likely not have complications like infection and bleeding.
Completely healed 2 years or more after thyroidectomy, with a scar.