In vitro bactericidal effect of low‐dose ultraviolet B in patients with acne

Comparison of the clinical efficacy of NBUVB and NBUVB with benzoyl peroxide/clindamycin in progressive macular hypomelanosis

“…In a previous report, growth of Propionibacterium was inhibited at the 300 mJ/cm 2 of NBUVB 10 . In addition, a suberythematogenic dose of UVB significantly decreased the number of colonies of P. acne in another study 11 . Therefore, the antimicrobial effects in the treatment area of mono‐NBUVB could result in therapeutic effects similar to comb‐NBUVB treatment.…”

Long‐term exposure to low levels of ambient UVB are associated with a decreased risk of moderate‐to‐severe acne: A retrospective cohort study in college students

“…Colonization of C. acnes can trigger the release of proinflammatory cytokines IL‐12 and IL‐8 via activation of Toll‐like receptor 2 in monocytes 25 . In vitro experiments had confirmed UVB's ability on reducing C. acnes density at suberythemal doses 26 . And the sensitivity of C. acnes irradiated with monochromatic light (320–440 nm) was the highest at 320 and 415 nm while decreased with increasing wavelengths in the region of 320–380 nm 27 .…”

“…25 In vitro experiments had confirmed UVB's ability on reducing C. acnes density at suberythemal doses. 26 And the sensitivity of C. acnes irradiated with monochromatic light (320-440 nm) was the highest at 320 and 415 nm while decreased with increasing wavelengths in the region of 320-380 nm. 27 Another study that investigated the antibacterial effectiveness of NBUVB lamp (313 nm) versus UVA1 lamp (345-440 nm) for Propioni bacteria only demonstrated a significant inhibition by NBUVB even under a minimum dose of 0.30 J/cm 2 , and this revealed different bactericidal capacities of UVB and UVA.…”

Is Cutibacterium (previously Propionibacterium) acnes a potential pathogenic factor in the aetiology of the skin disease progressive macular hypomelanosis?

“…Furthermore, in many cases recurrence of the condition occurred, although some patients retained a degree of clinical improvement. While such observations question the pathogenic role for C. acnes in PMH, a key difference between these studies and that of Relyeld et al 25 relates to the use of NB‐UVB rather than UVA NB‐UVB has been shown, in vitro , to have antibacterial effects on cutibacteria which is not observed with UVA, potentially explaining the contradictory results 48,49 . It is interesting to note, however, that in the study of Selim et al 6 only two PMH patients had hypopigmented lesions that demonstrated fluorescence under a Wood’s lamp indicating absent or low levels of C. acnes , or colonization with low porphyrin‐producing strains, while data from Sim et al 21 in relation to Wood’s lamp analysis was not described.…”

“…While such observations question the pathogenic role for C. acnes in PMH, a key difference between these studies and that of Relyeld et al 25 relates to the use of NB-UVB rather than UVA NB-UVB has been shown, in vitro, to have antibacterial effects on cutibacteria which is not observed with UVA, potentially explaining the contradictory results. 48,49 It is interesting to note, however, that in the study of Selim et al 6 only two PMH patients had hypopigmented lesions that demonstrated fluorescence under a Wood's lamp indicating absent or low levels of C. acnes, or colonization with low porphyrin-producing strains, while data from Sim et al 21 in relation to Wood's lamp analysis was not described. In contrast, Hassan et al 9 found that topical (2% erythromycin lotion) and systemic (100 mg doxycycline b.i.d) antimicrobial treatments alongside NB-UVB for 3 months did give superior results compared to NB-UVB alone, and with no relapse in a 6 month follow-up period.…”