Low-intensity laser therapy evaluation in the frequency of herpes labials recurrences: in vivo randomized blind study

Abstract

The herpes simplex virus is present in 90% of the population, but it manifests in 20 to 40% of the world population as recurrent herpes labials. The recurrences of herpes labials are usually painful and it also represents a significant aesthetic problem. There is currently no drug able to reduce the number of labial herpes recurrences. The Low- Intensity Laser Therapy has shown promising results in reducing recurrences, however, controlled clinical trials are needed to confirm the efficacy of the therapy. Thus, the present study aims to evaluate the effectiveness of the application of low-intensity laser in the prevention of Herpes Simplex Labials recurrences through a randomized controlled clinical trial. 99 volunteers will be recruited to participate in the study, randomly divided into three study groups: Laser 1 (n = 33), Laser 2 (n = 33) and placebo (n = 33). Laser Group 1: The parameters used are: 100mW, 808nm, 1J, 10 seconds per point. There will be about 50-60 irradiation points, with a distance of 1 cm between them on the lips of the patient and perioral skin. The treatment will consist of two phases of irradiation: Phase 1 - consists in 10 sessions, 3 sessions per week, with an interval of 48 hours between them (Monday, Wednesday and Friday). Phase 2: After 6 months an additional 5 sessions are conducted, with an interval of 48 hours between them. Laser Group 2: Irradiation is performed in the same manner and with the same frequency as described above. The parameters used are: 100mW, 810nm, 2J, 20 seconds per point. Placebo: The laser is positioned at the same points and in the same manner as in Laser groups, however the parameters used are: 0mW and 0J. If during the treatment described above, the patient presents with recurrent herpes labials and this is not in the placebo group, the adopted protocol will vary according to the stage in which recurrence present: (A) Phase prodromal: The patient will be immediately submitted to 5 additional preventive sessions. (B) Phase vesicle or crust: If the vesicles have appeared, these will be drained with the aid of a needle and the photodynamic therapy will be done using methylene blue and the equipment set up on the following parameters: 100mW, 660nm and 4J. The crust stage photodynamic therapy will also be used on the region, with the protocol described above. The patient will be evaluated with according to frequency and labial herpes recurrence intensity prior to initiation of treatment, prior to Phase 2 and 6 months after the end of Phase 2. Analysis of the data will be evaluated statistically by non-parametric statistical test.