The role of pulsed light and heat energy (LHE) in acne clearance

J Cosmet Laser Ther. 2004 Jun;6(2):91-5. doi: 10.1080/14764170410035584.


Background: Propionibacterium acnes synthesize and store a large amount of porphyrins. Once the porphyrin is exposed to visible light it becomes chemically active and transfers to an excited state, resulting in the formation of singlet oxygen, which combines with cell membranes to destroy the P. acnes. This process is dependent on the rate of production of excited porphyrin molecules, which is influenced by the concentration of porphyrins, the concentration of photons, the temperature, and the wavelength of the photons.

Methods: Nineteen patients with mild to moderate acne underwent bi-weekly treatments for 4 weeks using the ClearTouch system. During each treatment, pulses of light and heat were applied. Each pulse used an average energy density of 3.5 J/cm(2), a pulse width of 35 ms, and a wavelength between 430 and 1100 nm.

Results: At the end of the eighth treatment, acne clearance for the non-inflammatory and inflammatory lesions was 63 +/- 21% and 50 +/- 32%, respectively. One month after the last treatment, the acne clearance for non-inflammatory and inflammatory lesions was 79 +/- 22% and 74 +/- 20%, respectively, with further improvement in acne clearance at 2 months after the last treatment (85 +/- 17% and 87 +/- 25%, respectively).

Conclusion: ClearTouch pulsed light and heat energy (LHE) technology is effective and safe for the treatment of acne vulgaris.

MeSH terms

  • Acne Vulgaris / radiotherapy*
  • Acne Vulgaris / therapy
  • Adolescent
  • Adult
  • Female
  • Gram-Positive Bacterial Infections / radiotherapy*
  • Humans
  • Hyperthermia, Induced / methods*
  • Male
  • Phototherapy / methods*
  • Porphyrins / metabolism
  • Propionibacterium acnes / metabolism*
  • Singlet Oxygen / metabolism
  • Treatment Outcome


  • Porphyrins
  • Singlet Oxygen