TLDR Sunlight simulation causes skin inflammation, with different skin types reacting at different levels of exposure.
A double-blinded, randomized, controlled clinical study was conducted on 53 healthy female volunteers with skin types I-VI to examine the response to a low simulated solar radiation (SSR) dose series on erythema, skin color, blood flow/flux, and superficial plexus diameter over 4 weeks. The study found that the minimal dose for erythema induction varied within sub-skin types. Blood flow, blood flux, and L and a* values showed significant increases at 24 hours and dose differences among sub-skin types. The study also found that skin types I-II showed consistent inflammation responses at a minimal 0.8-1.0x minimal erythema dose (MED), whereas skin types III-IV and V-VI at a minimal 1.5x MED. This suggests an adjustment factor for MED determination based on ITA° values for skin types III-IV. The results demonstrate a possible model and treatment window to alleviate inflammation in different skin types.View this study on jidonline.org →