The effect of long-pulsed 1064 nm Nd:YAG laser-assisted hair removal on some skin flora and pathogens: an in vivo study

Abstract

Background The effect of NDYag on normal skin flora and pathogenic microbes has not been studied. Objectives Evaluation of immediate (before versus after each session) and delayed (pre-first session versus pre-fourth session) antimicrobial effect of Nd:YAG laser-assisted hair removal. Methods Thirty females scheduled for axillary Nd:YAG laser hair removal were included. Skin swabs were collected from the vault of the dominant axilla before and after each of the four sessions. Bacteriological cultures were performed to record the counts of total aerobes, total anaerobes, lipophilic bacteria, total staphylococci, Staphylococcus epidermidis (S. epidermidis), S. saprophyticus, S. hominis, and S. aureus. Reported changes in sweat odour and folliculitis (if present) were recorded. Results S.hominis was the predominant species in all subjects before and after all sessions. Counts of total aerobes, total anaerobes, lipophilic bacteria, total staphylococci, and S.hominis significantly decreased after all 4 sessions. A significant reduction was noted in the median colony counts before the fourth session as compared to the baseline count before the first session in total aerobes (278.9 versus 126.3 × 105 CFU/cm2, p = 0.003), total anaerobes (338.7 versus 103.7 × 105 CFU/cm2, p = 0.002) and total staphylococci (248.5 versus 105.0 × 105 CFU/cm2, p = 0.004). Most subjects reported worsened or unchanged axillary sweat odour. There was a statistically significant positive correlation between sweat odour and the counts of total aerobes (r = 0.433, p = 0.017), total anaerobes (r = 0.377, p = 0.040), total staphylococci (r = 0.383, p = 0.036) and S.hominis (r = 0.497, p = 0.005) ; lower counts were associated with a worsened odour. Limitations Small sample size; few laser sessions; short follow-up; subjective assessment of sweat odor and quantity. Conclusions Laser caused an immediate and delayed reduction in axillary aerobes, anaerobes, lipophilic bacteria, and staphylococci. This form of dysbiosis might lead to sweat odour changes.