Primary linear repair remains a fundamental and common means of closing skin defects;
however, to date, there are no clinical studies currently within the medical literature
that explore the potential influence that sunlight exposure has on the cosmetic outcome
of surgical site cutaneous scars. Therefore, this study aims to determine the potential
effects of sun protection on post-surgical scar cosmesis following linear repairs on
sun-exposed areas of the face, hairless scalp, and neck.
It has been thought that sun exposure is associated with a higher chance of erythema and
dyspigmentation in cutaneous wounds, however, this remains unproven and findings
pertaining to this topic remain largely confined to animal studies. In one study,
researchers found that the wounds of rats chronically exposed to UVA radiation exhibited
diminished wound contraction during the healing process compared to non-irradiated
controls. Another study simulated UV radiation before and after laser treatment on
vascular skin lesions in groups of hairless mice. In the postoperative UV-irradiated
group, the mice skin displayed significant fibrosis, slower healing, and marked
hyperpigmentation. A different group of researchers explored the effect of UVA light
exposure on wound pigmentation on scars with and without dry tattooing. This study found
that dry tattooing with UVA light exposure demonstrated significant improvement of
hypopigmented scars. The researchers of this study hypothesized that the light exposure
led to an inflammation-driven hyperpigmentation response. A separate study hypothesized
that UV exposure may be beneficial for wound healing by stimulating melanocyte
distribution via keratinocyte-melanocyte cross-talk, and thus, preventing
hypopigmentation. Irregularity in the pigmentation of healing scars remains a large
insecurity of patients and has led to their desire for surgical corrections of these
scars. These researchers suggested that UV exposure will promote melanin production, and
thus, potentiate a protective effect against further UV damage and wound
hypopigmentation.
Skin color changes provide information and clues about certain pathologies, disease
progression, and patient response to treatment. Factors such as melanin vascularity
contribute to skin color. Historically, this evaluation of skin color has been
subjective, however, objective analysis is now possible by means of colorimeters.
Cutaneous color changes can be quantified using the standardized CIELAB system, which
measures color light intensity, as well as red/green and yellow/blue intensity. Following
Mohs micrographic surgery, the colorimeter can be used as an objective measurement to
assess scar hyperpigmentation and vascularity.
