Does sun exposure pose risks after surgery?

Whether the procedure is cosmetic surgery such as rhinoplasty, liposuction, hair grafting or a cryolipolysis, dermatological surgery such as excision of a mole or the removal of a cyst, or reconstructive surgery, the attentive post-operative care is essential. Common instructions include sun avoidance and skin protection.

Avoiding sun exposure after surgery allows proper skin healing.

After surgery, the skin undergoes an orchestrated process of healing that occurs in three stages. First, it enters an inflammatory phase lasting several days and triggers an immune response to clean the wound and prevent infection. Second, during the proliferative phase, which lasts two to four weeks, fibroblasts produce collagen. New blood vessels form and the skin rebuilds. Third, the remodeling phase, which can last up to two years, stabilizes the scar: collagen reorganizes, the area becomes more flexible, and pigmentation adjusts. Even if the surface appears closed, the skin remains fragile long after surgery. Skin that lacks sun protection after surgery faces the following risks:

• Delayed wound healing: UV rays are known to stimulate free radical production in the skin. Free radicals are unstable compounds that seek to react with other molecules to form electron pairs. They damage cells, DNA, and proteins. They impair fibroblasts—cells that synthesize granulation tissue during healing—and keratinocytes, which close the epidermis. This disruption delays skin reconstruction.

• Hyperpigmentation: When skin is exposed to UV rays from the sun, the process of melanogenesis during which melanin is synthesized in melanocytes is initiated. After surgery, the skin enters a remodeling phase. Its barrier function is more fragile than usual. Local inflammation sensitizes melanocytes to UV rays. Under sun exposure, these cells produce excess melanin, which is then transferred to keratinocytes, causing abnormal, long-lasting discoloration of the scar.

• Keloid formation: Sun exposure maintains an inflammatory environment that triggers excessive fibroblast activation. These cells overproduce collagen in a disorganized way, mainly types I and III. The result is a chaotic collagen fiber deposit in the skin, forming raised scars that extend beyond the surgical site. This scar type is called keloidal or keloid. Keloid scars can cause functional and aesthetic discomfort, pain, and itching. The risk is higher in individuals with darker phototypes, who have a pronounced pigmentary and inflammatory response. That is why, contrary to misconceptions, sun protection is important for darker skin tones.