ABSTRACT
Background: Regular exposure to ultraviolet rays is high in India, where most Indians present Fitzpatrick skin phototypes IV and V. Aims: To evaluate the efficacy and compare the effectiveness of two sunscreen products on Indian skin types IV and V with pigmentation irregularities. Methods: A randomized, uncontrolled and investigator-blinded, single-center study enrolled adult men and women (18–45 years) with Fitzpatrick skin phototypes IV (28° < individual typological angle <10°) and V (10° < individual typological angle < −30°) with pigmentary abnormalities seen on the face in adults (actinic lentigines and postinflammatory hyperpigmentation), who did not use sunscreens. Participants were randomized (1:1) to either of the two marketed sunscreen products, Product A (sun protection factor 50 PA+++) or Product B (sun protection factor 19 PA+++), applied twice daily before sun exposure for ≥2 h. Primary objectives aimed at assessing possible improvement in hyperpigmented spots and overall skin appearance after 12 weeks of use. Evaluation of skin radiance and skin color was done by means of L'Oréal color chart and colorimetric measurements (Chromameter®). Results: Among the 230 enrolled participants, 216 (93.91%) completed the study. The clinical assessment of the density of pigmented spots and skin radiance showed significant (P < 0.001) improvement in both groups during all visits. The qualitative (participant perception) and quantitative (Chromameter®) data indicated improvement in pigmentation from Week 0 to Week 12. Both products were well-tolerated. Limitations: The study was conducted over a rather short period of time (12 weeks) at a single location. Conclusions: This is the first study conducted on Indian skin phototypes IV and V under real-life conditions. It demonstrated the effect of regular sunscreen usage in the prevention of certain signs of skin photoaging such as increased pigmentation or pigmentary abnormalities, thus providing support and assistance to clinicians in suggesting the use of efficient sun-screening products to patients.
ABSTRACT
Solar ultraviolet (UV) radiation reaching the earth is a combination of UVB (290-320 nm) and UVA (320-400 nm) wavelengths. Since UVA is less energetic than UVB, UVB has long been thought to be the factor responsible for the damaging effects of solar radiation. But with modern tools such as in vitro models, it has been proven that UVA plays a major role. The objective of this review is to show how skin may be exposed to UV light and to highlight the clinical aspects of UV-induced skin damages with the respective contribution of UVB or UVA. Even if UVA is less energetic than UVB, it is more abundant and penetrates deeper into the skin, reaching as far as the dermis. Various factors also influence skin exposure to UV light: the latitude, season, and time of the day. Acute as well as chronic sun exposure induces short- and long-term clinical damages. Erythema and pigmentation are immediate responses of normal human skin exposed to UV radiation. The long-term effects are photoaging and photocarcinogenesis. In particular, UVA appears to play a major role in the deterioration of dermal structure leading to the photoaged appearance of the skin.