Synergistic Effects of Solar Exposure and Skin Sensitivity on Skin Aging: A Clinical Study Using Multimodal...

Solar exposure is the primary extrinsic factor contributing to skin aging. Sensitive skin, characterized by impaired barrier function and heightened reactivity, may be more vulnerable to solar-induced damage. However, the potential interaction between skin sensitivity and solar exposure in accelerating skin aging has not been systematically quantified using objective clinical measurements.

To investigate the interactive effects of skin sensitivity and solar exposure on multiple aging-related skin parameters using multimodal noninvasive measurement techniques.

This single-center observational study enrolled 124 healthy Chinese female volunteers aged 25-34 years. Participants were categorized according to skin sensitivity (sensitive vs. nonsensitive) and occupational solar exposure (indoor vs. outdoor), forming four groups (n = 31 per group): indoor sensitive (IS), outdoor sensitive (OS), indoor nonsensitive (INS), and outdoor nonsensitive (ONS). Skin barrier function, surface morphology, elasticity, dermal structure, and sebum secretion were evaluated using a series of noninvasive instruments. Two-way analysis of variance (ANOVA) was used to assess the main effects and interaction effects of skin sensitivity and solar exposure.

Significant interaction effects between skin sensitivity and solar exposure were observed for seven aging-related parameters, including transepidermal water loss (TEWL), stratum corneum thickness (SCT), second harmonic generation (SHG), autofluorescence (AF), skin roughness, nasolabial fold length, and sebum secretion (p < 0.05). The outdoor sensitive group exhibited the most pronounced aging phenotype, characterized by increased TEWL, reduced stratum corneum thickness, decreased SHG and AF signals, greater skin roughness, and longer nasolabial folds.

Skin sensitivity and solar exposure exhibit a significant synergistic effect in the skin aging process. Individuals with sensitive skin under chronic solar exposure demonstrate more severe barrier dysfunction, dermal matrix degradation, and wrinkle formation. These findings suggest that sensitive skin represents a high-risk phenotype for photoaging and highlight the importance of combined barrier repair and effective photoprotection strategies for this population.