Side effects from intense pulsed light: Importance of skin pigmentation, fluence level and ultraviolet radiation-A randomized controlled trial.

BACKGROUND AND OBJECTIVE: Intense pulsed light (IPL) is a mainstream treatment for hair removal. Side effects after IPL are known, but risk factors remain to be investigated. The objective of this study was to assess the contribution of skin pigmentation, fluence level, and ultraviolet radiation (UVR) on IPL-induced side effects. METHODS: The study was a blinded, randomized intra-individual controlled trial including 16 healthy subjects with Fitzpatrick Skin Types (FST) II-V. Three test areas were each divided into four sites, randomized to a single IPL exposure of 22, 34, 46 J/cm2 or triple stacking of 46 J/cm2 . Areas were subsequently randomized to no UVR or single solar-simulated UVR exposure of 3 Standard Erythema Dose at 30 minutes or 24 hours after IPL. Each area had a corresponding control, resulting in 15 treatment sites. Follow-up visits were scheduled up to 4 weeks after IPL. Outcome measures were: (i) blinded clinical skin reactions; (ii) objectively measured erythema and pigmentation; (iii) pain measured by visual analog scale (VAS); (iv) histology (H&E, Fontana-Masson); and (v) mRNA-expression of p53. RESULTS: Fifteen subjects with FST II-IV completed the protocol. IPL induced a wide range of skin reactions, including erythema (87% of subjects), purpura (27%), blisters (20%), edema (13%), crusting (13%), hyper- (60%), and hypopigmentation (20%). Darker skin pigmentation and increasing IPL fluence were determinants for IPL-induced side effects (P ≤ 0.002), while a single exposure of UVR did not exacerbate side effects (P ≥ 0.180). Clinical findings were confirmed objectively by reflectance spectrometry and qualitatively by histological changes in skin architecture, inflammatory infiltration, and pigmentation. Marker of cellular DNA damage, that is, p53, did not increase after IPL (P ≥ 0.24). CONCLUSIONS: Skin pigmentation and IPL fluence are major determinants of side effects after IPL exposure, while a single exposure to three SED of UVR at 30 minutes or 24 hours after IPL, does not amplify such side effects. Lasers Surg. Med. 49:88-96, 2017. © 2016 Wiley Periodicals, Inc.

Ultraviolet radiation after exposure to a low-fluence IPL home-use device: a randomized clinical trial.

The prevailing advice is to avoid sun exposure after intense pulsed light (IPL) hair removal. However, no systematic evaluation of ultraviolet radiation (UVR) after IPL hair removal exits. Therefore, we investigated the occurrence of side effects in subjects receiving solar-simulated UVR after a low-fluence IPL treatment with a home-use device. Sixteen subjects with Fitzpatrick skin types (FST) II-V were enrolled. Three constitutive buttock blocks (4.4 × 6.4 cm) were each subdivided into four sites, randomized to one IPL exposure of 0, 7, 8, or 10 J/cm2 (spectral output 530-1100 nm). Blocks were randomized to no UVR or three standard erythema doses (SEDs) UVR either 30 min or 24 h after IPL. Follow-up visits were 48 h, 1 week, and 4 weeks after IPL. Outcome measures were (i) clinical skin reactions, (ii) reflectance measurements of erythema and pigmentation, and (iii) pain. Subjects with FST II-IV experienced no skin reactions up to 4 weeks after IPL, neither erythema, edema, blisters, crusting, textual, nor pigment changes. Reflectance confirmed no change in erythema and pigmentation (p ≥ 0.090). UVR exposure induced erythema and increased pigmentation. The combination of IPL and UVR induced skin reactions not different to responses from UVR (IPL-UVR vs. UVR, p ≥ 0.164). Pain was generally low (median 1, range 0-4) and correlated positively with fluence and pigmentation (Spearman's rho ≥ 0.394, p < 0.001). One subject with FST V experienced perifollicular hyperpigmentation after IPL and slightly more intense when exposed to UVR. A single UVR exposure of three SEDs either shortly or 1 day after low-fluence IPL causes no amplification of skin responses in constitutive skin of individuals with FST II-IV.

The role of natural and UV-induced skin pigmentation on low-fluence IPL-induced side effects: a randomized controlled trial.

BACKGROUND AND OBJECTIVES: The risk of adverse skin effects following light-based hair removal is greater in pigmented skin based on the theory of selective photothermolysis. Thus sunlight-induced pigment i.e., facultative pigmentation, increases the risk of adverse skin effects, perhaps disproportionately. The aim of this study was to evaluate the influence of constitutive and facultative skin pigmentation on low-fluence intense pulsed light (IPL)-induced adverse skin effects. STUDY DESIGN/MATERIALS AND METHODS: Twenty-one subjects with Fitzpatrick skin type II-IV were enrolled. Two buttock blocks were randomized to receive 0 or 8 solar simulated ultraviolet radiation (UVR) exposures of consecutively increasing Standard Erythema Doses (2-4 SED). Each block was subdivided into four sites, randomized to receive IPL of 0, 7, 8, or 10 J/cm(2) , once a week for 3 weeks. Biopsies were taken 16-24 hours after the first IPL exposure and subjects were seen 1 and 4 weeks after the last IPL exposure. Outcome measures were: (i) skin reactions, (ii) pain, (iii) mRNA expression of pigment-markers microphthalmia-associated transcription factor (MITF) and pro-opiomelanocortin (POMC), and (iv) clinical appearance of biopsy wounds. RESULTS: Skin pigmentation increased after UVR (baseline median 13.8%, after UVR 28.1%, P = 0.0001) in all skin types. Subjects reported low pain intensities (median 1.5, scale 0-10) and experienced transient erythema immediately after IPL exposure. No persistent erythema, blisters, crusting, textual, or pigment changes were observed. The risk of erythema and pain intensities increased with IPL dose and skin pigmentation (P < 0.03). There was no difference in pain or skin reactions in skin with similar degree of natural and facultative pigmentation (P ≥ 0.104). Expression of cellular pigment-markers was not influenced by IPL exposure, neither in constitutive nor in facultative pigmented skin. Clinical appearance of biopsy wounds was unaffected by IPL exposure. CONCLUSION: The prevalence and intensity of low-fluence IPL-induced adverse skin effects depended on IPL dose and skin pigmentation regardless of the origin, i.e., constitutive versus UV induced.