Scars are visible reminders of past injuries. Hair typically does not grow on these areas, a frequent characteristic of scarred skin.
The Biology of Scar Tissue
Normal skin contains hair follicles, sweat glands, and sebaceous glands. When skin is injured, the body forms scar tissue. Unlike healthy skin, scar tissue lacks these specialized accessory structures; hair follicles are absent or destroyed.
Scar tissue also differs structurally from uninjured skin. Healthy skin has collagen fibers in a random, interwoven pattern, providing flexibility and strength. In contrast, scar tissue has collagen fibers organized in dense, parallel bundles. This arrangement contributes to the stiffer, less elastic nature of scars. Scar tissue also has a reduced blood supply, affecting its ability to support biological processes, including hair growth.
Factors Influencing Hair Growth on Scars
Hair growth on a scar depends on the extent of the original injury. Superficial wounds, like minor abrasions, often heal without significant scarring, allowing some hair regrowth if follicles remain intact. Deeper injuries, such as severe burns or cuts, typically cause irreversible damage to hair follicles, making natural hair regrowth improbable.
Once hair follicles are destroyed within scar tissue, hair loss in that area becomes permanent. Scar types, including atrophic (pitted), hypertrophic (raised), or keloid (excessively raised), inherently lack follicular structures. The maturity of a scar also plays a role; once fully formed, its characteristics, including the absence of hair growth, are generally established.
Options for Hair Restoration on Scars
For individuals seeking to restore hair to scarred areas, several approaches are available. Hair transplantation is often considered the most effective method. This procedure involves taking healthy hair follicles from a donor area and implanting them into the scar tissue. The scar’s blood supply and tissue stiffness can influence success, and multiple sessions may be necessary to achieve desired density. Graft survival rates in scarred tissue can be around 81%, sometimes rivaling rates on unscarred skin.
Less invasive options include microneedling and Platelet-Rich Plasma (PRP) therapy. Microneedling creates microscopic punctures to stimulate healing and collagen production, potentially improving the tissue environment and enhancing topical treatment absorption. PRP therapy uses concentrated growth factors from the patient’s blood to promote healing and tissue regeneration, often complementing other treatments to improve scarred skin’s receptiveness to hair growth. While these methods can improve skin quality, their ability to stimulate significant hair growth on fully scarred tissue is limited compared to transplantation.
Cosmetic camouflage techniques provide temporary solutions for concealing scars. Options include specialized makeup, hair fibers, or scalp micropigmentation (SMP). SMP involves tattooing tiny dots of pigment onto the scalp to create the illusion of hair follicles, blending the scar with surrounding hair. These non-surgical methods can reduce the visibility of scars and enhance aesthetic appearance.