Non-invasive diagnostic evaluation of phototherapeutic effects of red light phototherapy of acne vulgaris

Photodermatol Photoimmunol Photomed. 2008 Oct;24(5):244-8. doi: 10.1111/j.1600-0781.2008.00368.x.


Background: During the past few years, various phototherapeutic protocols with full-spectrum visible light or selected wavebands have been investigated in the treatment of acne vulgaris with variable results.

Methods: Fifteen women suffering from moderate acne vulgaris of the face were exposed to 20 J/cm(2) of broad-band red (lambda: 600-750 nm) light twice weekly for 4 weeks. In addition, with the aim to improve the present knowledge of the mechanisms of action of phototherapy, we measured skin sebum, pH, hydration and trans-epidermal water loss (TEWL). Lesions of the trunk were not irradiated and served as controls.

Results: A significant improvement of acne lesions and a significant decrease of skin sebum excretion and TEWL of the face were registered at the end of the therapy and at the 3-month follow-up visit. The results could be related to a reduced follicular colonization of Propionibacterium acnes, in that it was lethally damaged by photoactivated endogenous porphyrins.

Conclusion: The present findings seem to indicate that red light phototherapy may represent an effective, well-tolerated, safe, simple and inexpensive treatment option for moderate acne vulgaris.

Publication types

  • Clinical Trial

MeSH terms

  • Acne Vulgaris / pathology*
  • Acne Vulgaris / therapy*
  • Adolescent
  • Adult
  • Female
  • Humans
  • Hydrogen-Ion Concentration
  • Light*
  • Phototherapy*
  • Skin / pathology*
  • Water


  • Water