Aim: To develop a novel plasmonic nanosensing technique to monitor the exposure levels of UV light for sunlight disease prevention. Methods: Anisotropic gold nanoparticles were grown inside a UV photoresponsive fluid, which was previously exposed to UV radiation from different sources. The morphology and optical properties of the obtained nanoparticles were monitored by spectroscopy and microscopy. Results: The morphological and optical properties of the nanoparticles were dependent on the UV dose. The UV exposure levels were accurately correlated to the UV minimal doses to produce erythema to different skin types. Conclusion: This plasmonic nanosensing technique can be employed as novel sunlight-indexing tool for monitoring the dangerous level of skin exposure