An international survey of recalcitrant and recurrent tinea of the glabrous skin-A potential indicator of antifungal resistance.

BACKGROUND: There has been a global rise in cases of dermatophytosis and, in particular, recalcitrant and recurrent cases on tinea of the glabrous skin. This phenomenon, particularly prevalent in India, has been linked to the concerning rise of antifungal resistance. The challenge is amplified by a dearth of comprehensive, international data to understand the global scope and characteristics of such cases. OBJECTIVES: This study aims to collate international insights, focusing on areas outside Europe (as this was previously published), to map the extent and characteristics of clinical and, where possible, laboratory confirmed tinea of the glabrous skin through an online survey administered to dermatologists globally. METHODS: An online survey was distributed from February 2022 to July 2023 and captured data on respondents' experience of recalcitrant and recurrent tinea of the glabrous skin over the preceding 3 years. RESULTS: A total of 260 responses were received spreads across 36 countries, excluding Europe. In total, 91.7% reported seeing cases of recalcitrant or recurrent tinea of the glabrous skin over the preceding 3 years. Common anatomical sites affected were the trunk and groin. T. mentagrophytes and T. rubrum were the predominant species implicated, and there were low rates of laboratory confirmed dermatophyte resistance. CONCLUSIONS: The high rates of reported recalcitrant and recurrent tinea of the glabrous skin underscore an urgent need for global collaborative efforts and enhanced diagnostic measures. The findings advocate for the establishment of a standardized global disease registry, regulation of over-the-counter antifungal and steroid combinations, correlation of clinical suspicion with laboratory confirmed drug resistance and exploration of alternative therapeutic strategies to mitigate the burgeoning challenge of dermatophyte resistance.

Exploring treatment and antifungal resistance in an outbreak of tinea caused by Microsporum audouinii.

BACKGROUND: Microsporum audouinii has resurged recently. Infections with the dermatophyte are difficult to treat, which raises the question if we treat M. audouinii infections with the most effective antifungal (AF) agent. OBJECTIVES: The aims of this study was to investigate an outbreak of tinea capitis (TC) in Denmark, address the challenges in outbreak management and to conduct two reviews regarding previous outbreaks and minimal inhibitory concentration (MIC). METHODS: We used Wood's light, culture, direct microscopy, and PCR for screening and antifungal susceptibility testing (AFST) for treatment optimization. We performed two reviews to explore M. audouinii outbreaks and MIC values using broth microdilution method. RESULTS: Of 73 screened individuals, 10 had confirmed M. audouinii infections. Clinical resistance to griseofulvin was observed in 4 (66%) cases. While previous outbreaks showed high griseofulvin efficacy, our study favoured terbinafine, fluconazole and itraconazole in our hard-to-treat cases. AFST guided the choice of AF. Through the literature search, we identified five M. audouinii outbreaks, where differences in management included the use of Wood's light and prophylactic topical AF therapy. Terbinafine MIC values from the literature ranged from 0.002 to 0.125 mg/L. CONCLUSION: Use of Wood's light and preventive measurements were important for limiting infection. The literature lacked MIC data for griseofulvin against M. audouinii, but indicated sensitivity for terbinafine. The clinical efficacy for M. audouinii treatment was contradictory favouring both terbinafine and griseofulvin. AFST could have a key role in the treatment of difficult cases, but lack of standardisation of AFST and MIC breakpoints limits its usefulness.

Tumor necrosis factor-α inhibitor treatment of acne fulminans - a clinical and literature review.

Acne fulminans (AF) is a rare, serious, sudden-onset and long-lasting skin disease that causes scarring of face and body. Standard treatment with combined long-term isotretinoin and prednisolone is not always sufficient and has a well-known propensity for adverse effects leaving an unmet need for improved therapy. Case reports suggest that tumor necrosis factor (TNF)-α inhibitors may play a role in the management of AF. In a 3-year retrospective data collection from two dermatology centers and literature review of clinical cases of acne fulminans treated with anti-TNF-α therapy, three clinical cases and twelve literature cases were identified. A total of five different TNF-α inhibitors have been tested, with adalimumab being the most commonly used. Clinical response was seen after 1 month in 2/3 (67%) clinical cases and 5/12 (42%) literature cases, respectively, and treatment was successful in 2/3 (67%) and 11/12 (92%) after a median 3-7 months. All reported adverse effects were mild and reversible. Anti-TNF-α treatment may provide rapid improvement in patients with AF when initial treatment with isotretinoin and prednisolone fails. However, randomized controlled trials are lacking, and exact dosage and timing need to be explored before clinical implementation.

A survey of students' and junior doctors' confidence in diagnosing in skin of colour.

INTRODUCTION: To combat ethnic inequalities in health, medical students should be prepared to treat all patients. Denmark has become an increasingly diverse society and therefore needs a medical curriculum that reflects the change in population composition. This study aimed to assess if the dermatology curriculum in Denmark prepared medical students to diagnose dermatological diseases in patients with skin of colour (SoC). METHODS: From 20 September to 12 October 2022, a survey was distributed to medical students and junior doctors who had completed the dermatology curriculum at one of the medical schools in Denmark between 2010-2022. The participants were recruited mainly via Facebook. The statistical data were analysed in STATA, and free-text responses were analysed using thematic analysis. RESULTS: A total of 592 medical students (n = 285) and junior doctors (n = 307) completed the survey. In SoC, 43.9% and 32.6% felt confident to a poor or very poor degree in diagnosing dermatological diseases versus 5.9% and 2.5% in white skin. Among others, the respondents suggested to increase visual examples in the curriculum and integrate SoC in exams to increase their confidence level when diagnosing in SoC. CONCLUSION: Danish medical students and junior doctors are significantly less confident when diagnosing dermatological diseases in SoC than in white skin. Revision of the dermatology curriculum is needed to increase the students' confidence level and knowledge of SoC to prepare them to treat all patients, ultimately reducing ethnic inequalities in health. FUNDING: None. TRIAL REGISTRATION: Not relevant.

Laser and intense pulsed light in the treatment of hidradenitis suppurativa.

Treatment of hidradenitis suppurativa (HS) requires a combination of medical, surgical, and lifestyle interventions. Intense pulsed light (IPL) and lasers have been reported to be useful. The aim of this review is to find the evidence supporting IPL and laser treatment of HS and to provide guidance for the management of specific HS lesions. We searched PubMed and Web of Science for "laser" and "hidradenitis suppurativa" on April 6, 2022. Inclusion criteria were >10 patients, reported follow-up, English language, and human subjects with a diagnosis of HS. A total of 724 articles were screened, but only 17 studies qualified for inclusion (IPL (n = 4), Nd:YAG (n = 6), CO2 laser (n = 6), and intralesional treatment (n = 2). The majority of the studies had a low (n = 10) or moderate (n = 7) evidence level. Treatment effect was noticed in studies using IPL and Nd:YAG (hair reduction). CO2 laser was used for surgery with a success rate ranging from 70.7% to 96.7%. CO2 laser is useful for surgery of stationary HS lesions, but it is difficult to draw a conclusion on the use of IPL and Nd:YAG (hair reduction) as the studies were too heterogeneous to perform a meta-analysis.

Two Novel Human Leukocyte Antigen Alleles Are Associated with Decreased Risk of Onychomycosis in a Large Cohort of Danish Blood Donors.

Introduction: Antigen presentation and antimicrobial immune responses involve the human leukocyte antigen (HLA) system. Onychomycosis is primarily caused by dermatophytes and affects around 5.5% of the population worldwide. Yet, only limited data exist on the associations between the HLA system and onychomycosis. Thus, the objective of the study was to investigate if there is an association between HLA alleles and onychomycosis. Methods: Participants in the Danish Blood Donor Study were defined as cases of onychomycosis and controls based on antifungal prescriptions in the national prescription registry. Associations were investigated using logistic regressions adjusted for confounders and were Bonferroni corrected for multiple tests. Results: A total of 3,665 participants were considered onychomycosis cases, and 24,144 participants were considered controls. We found two protective HLA alleles of onychomycosis: DQB1*06:04, odds ratios (OR) 0.80 (95% confidence interval (CI) 0.71-0.90), and DRB1*13:02, OR 0.79 (95% CI: 0.71-0.89). Conclusion: The finding of two novel protective alleles of onychomycosis indicates that certain HLA alleles have certain antigen presentation properties affecting the risk of fungal infection. These findings may provide the basis for future research identifying immunologically relevant antigens of fungi causing onychomycosis, which could ultimately lead to targets of new drugs with antifungal effects.

Primary skin abscess microbiota a systematic review.

An abscess is a collection of pus forming a cavity in the tissue, for example, the skin. They are generally perceived as the result of infection but infection is not mandatory for the diagnosis. Skin abscesses may occur independently (primary) or be part of other diseases such as the recurrent inflammatory skin disease hidradenitis suppurativa (HS). HS is noninfectious but nevertheless abscesses are a common differential diagnosis. The purpose of this study is to review the microbiome of bacteria positive primary skin abscesses in order to explore the reported microbiota. EMBASE, MEDLINER, and COCHRANE LIBRABRY were searched on 9th of October 2021 for microbiome, skin, and abscesses. Studies with more than 10 patients reporting the microbiome in human skin-abscesses were included and studies with abscess microbiota sampled from HS patients, microbiota not sampled from skin-abscesses, missing information on microbiome data, sampling bias, studies in other language than English or Danish, reviews and meta-analyses were excluded. In total 11 studies were included for further analysis. S. aureus is likely to dominate the microbiome of bacteria positive primary skin abscesses in contrast to the polymicrobial microbiome of HS.

Symptoms of attention deficit hyperactivity disorder are associated with Hidradenitis suppurativa in Danish blood donors.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease associated with psychiatric comorbidity. Attention deficit hyperactivity disorder (ADHD) is a mental disorder associated with systemic and skin inflammation such as psoriasis and atopic dermatitis. Whether HS symptoms are associated with ADHD symptoms remains unexplored. Thus, the aim of this study was to explore the possible association between HS and ADHD. Participants in the Danish Blood Donor Study (DBDS) were included in this cross-sectional study during 2015-2017. The participants provided questionnaire data on screening items of HS, ADHD symptoms (ASRS-score), and depressive symptoms, smoking and body mass index (BMI). A logistic regression with HS symptoms as a binary outcome predicted by ADHD adjusted for age, sex, smoking, BMI, and depression was conducted to investigate the association between HS and ADHD. A total of 52,909 Danish blood donors were included in the study. Of these were 1004/52,909 (1.9%) considered participants with HS. Of the participants with HS, 74/996 (7.4%) screened positive of ADHD symptoms, while only 1786/51,129 (3.5%) of the participants without HS screened positive of ADHD. Adjusted for confounders, ADHD was positively associated with HS, odds ratio 1.85 (95% confidence interval: 1.43-2.37). Psychiatric comorbidity of HS is not limited to depression and anxiety. This study shows a positive association between HS and ADHD. Further research on the biological mechanisms behind this association is warranted.

A Review of Antifungal Susceptibility Testing for Dermatophyte Fungi and It's Correlation with Previous Exposure and Clinical Responses.

Background: An increase in the number of recurrent and recalcitrant dermatophytoses calls for a tool to guide the clinician to correlate in vitro minimum inhibitory concentration (MIC) data, antifungal treatment with clinical outcomes. This systematic review aims to explore a possible correlation between one aspect of this, previous antifungal exposure, and clinical outcomes. Methods: A systematic literature search for articles on previous antifungal treatment, treatment outcome, susceptibility methods used, organism (genus/species), and MIC values was conducted. Results: A total of 720 records were identified of which 19 articles met the inclusion criteria. Forty percent of the cases had contact with or travel to India, 28% originated from or had traveled to other countries where treatment unresponsive tinea infections had been reported. Tinea corporis was the most common clinical presentation and the species involved were Trichophyton (T.) indotineae and T. rubrum, followed by T. mentagrophyte/interdigitale complex and T. tonsurans. Nearly all patients had previously been exposed to one or more antifungals. The studies were too heterogeneous to perform a statistical analysis to test if previous antifungal exposure was related to resistance. Conclusions: Only a few studies were identified, which had both sufficient and robust data on in vitro susceptibility testing and clinical treatment failure. Further research on the value of susceptibility testing to improve clinical practice in the management of dermatophyte infections is needed.

Systematic review of the prevalence of onychomycosis in children.

Onychomycosis is one of the most common nail diseases in adults but is described as infrequent in children. Data are, however, scattered and diverse. Studies have nevertheless suggested that the prevalence of onychomycosis is increasing in children lately and the aim of this review was therefore to examine this problem. Two authors individually searched PubMed, Embase, and Cochrane Library for articles on epidemiology and prevalence of onychomycosis in children. The literature search was conducted in accordance per PRISMA guidelines. In total 1042 articles were identified of which 23 were eligible for inclusion. One of the articles presented two studies and a total of 24 studies were therefore included. Seventeen studies presented data of the prevalence of onychomycosis in children in the general population and seven studies among children visiting a dermatological and pediatric department or clinic. The prevalence ranged from 0% to 7.66% with an overall discrete increase of 0.66% during the period 1972 to 2014 in population studies (not statistically significant). This review supports a trend towards an increased prevalence of onychomycosis in children, albeit based on a paucity of studies. The data suggests an increasing prevalence of onychomycosis with age, and co-infection with tinea pedis (reported in 25% of the studies). The most common pathogen reported was Trichophyton rubrum and onychomycosis was more prevalent in toenails compared to fingernails. The general characteristics of onychomycosis in children are thus similar to those described in adults.

Correction: Astvad et al. Increasing Terbinafine Resistance in Danish Trichophyton Isolates 2019-2020. J. Fungi 2022, 8, 150.

In paragraph four of the discussion in the original article [...].

Disinfection trials with terbinafine-susceptible and terbinafine-resistant dermatophytes.

BACKGROUND: Treatment of tinea pedis and onychomycosis is complicated by high rates of reinfection and the emergence of terbinafine-resistant strains of Trichophyton spp. Effective disinfection of contaminated socks is an important measure. Appropriate washing reduces the risk of reinfection and is paramount in treating tinea pedis and onychomycosis. OBJECTIVES: The aim of this study was to describe the effect of commonplace disinfection methods using socks pieces inoculated with terbinafine-resistant or terbinafine-susceptible isolates of Trichophyton spp. METHODS: Sock pieces were inoculated with seven terbinafine-resistant isolates of Trichophyton spp. with known mutations in the SQLE-gene (T. rubrum (n = 3), T. interdigitale (n = 1) and T. indotineae (n = 3)) and six terbinafine-susceptible isolates of Trichophyton spp. (T. rubrum (n = 3) and T. interdigitale (n = 3)). Methods of disinfection included soaking in a quaternary ammonium (QAC) detergent (0.5, 2 and 24 h), freezing at -20°C (0.5, 12 and 24 h), domestic and steam washing (both at 40°C with detergent). Sock pieces were cultured for 4 weeks following disinfection. The primary end point was no growth at the end of week 4. RESULTS: Soaking in a QAC-detergent for 24 h procured at disinfectant rate of 100% (13/13), whilst soaking in 0.5 and 2 h had a disinfectant rate of 46.2% (6/13) and 84.6% (11/13), respectively. Domestic washing (40°C with detergent) produced a disinfectant rate of 7.7% (1/13). Freezing at -20°C (0.5, 12 and 24 h) and steam washing (40°C with detergent) had no disinfectant properties. CONCLUSIONS: Soaking in a QAC-detergent for 24 h effectively disinfected sock pieces contaminated with dermatophytes.

Increasing Terbinafine Resistance in Danish Trichophyton Isolates 2019-2020.

Terbinafine resistance in Trichophyton species has emerged and appears to be increasing. A new EUCAST susceptibility testing method and tentative ECOFFs were recently proposed for Trichophyton. Terbinafine resistance and target gene mutations were detected in 16 Danish isolates in 2013-2018. In this study, samples/isolates submitted for dermatophyte susceptibility testing 2019-2020 were examined. Species identification (ITS sequencing for T. mentagrophytes/T. interdigitale species complex (SC) isolates), EUCAST MICs and squalene epoxidase (SQLE) profiles were obtained. Sixty-three isolates from 59 patients were included. T. rubrum accounted for 81% and T. mentagrophytes/T. interdigitale SC for 19%. Approximately 60% of T. rubrum and T. mentagrophytes/interdigitale SC isolates were terbinafine non-wildtype and/or had known/novel SQLE mutations with possible implications for terbinafine MICs. All infections with terbinafine-resistant T. mentagrophytes/interdigitale SC isolates were caused by Trichophyton indotineae. Compared to 2013-2018, the number of patients with terbinafine-resistant Trichophyton isolates increased. For T. rubrum, this is partly explained by an increase in number of requests for susceptibility testing. Terbinafine-resistant T. indotineae was first detected in 2018, but accounted for 19% of resistance (4 of 21 patients) in 2020. In conclusion, terbinafine resistance is an emerging problem in Denmark. Population based studies are warranted and susceptibility testing is highly relevant in non-responding cases.

An Increase in Specialist Treatment for Onychomycosis: An Unexplained Tendency. A Retrospective Study of Patients Treated for Onychomycosis in Danish Hospitals from 1994 to 2018.

Onychomycosis is a common disease with a significant negative impact on quality of life. While the disease is usually manageable in general practice, a proportion of patients need specialist treatment in academic hospital clinics. However, it is an unknown question whether the incidence in those needing specialist treatments is changing. Furthermore, the comorbidity burden in this patient population severely affected by onychomycosis has never been characterized. We conducted a retrospective study on patients treated for onychomycosis in Danish hospitals from 1994 to 2018. The cohort was observed for 24 years, and the data comprise 7.2 million Danes and their hospital diagnoses. A disease trajectory algorithm was used to examine the comorbidity burden in the cohort. A total of 2,271 patients received hospital treatment for onychomycosis during the time period, of which 1358 (59.8%) were men. The data show an increase in the incidence of hospital-treated cases since 2012 and that the most common comorbidities in this patient population include cardiovascular disease, alcohol-related diagnoses, and diabetes. One explanation of the increase in specialist treatment may include a general increase in patients with decreased resilience to fungal disease. This lack of resilience may both include an increasing elderly population with atherosclerosis, diabetes, and immunosuppression but also a potential increase in patients treated with immunosuppressive agents. Another possible explanation may include a shift in patient expectations in the case of treatment failure. Thus, patients may have an increasing demand for specialist treatment. While our data document an increase in the number of patients in need of specialist treatment for onychomycosis, we suggest future research to examine the general incidence of onychomycosis but also whether this increase in an apparently recalcitrant disease may be attributed to increased antifungal resistance, more specialist treatment options, or increased attention to dermatomycoses.

The Emerging Terbinafine-Resistant Trichophyton Epidemic: What Is the Role of Antifungal Susceptibility Testing?

BACKGROUND: Dermatophytosis is commonly encountered in the dermatological clinics. The main aetiological agents in dermatophytosis of skin and nails in humans are Trichophyton (T.) rubrum, T. mentagrophytes and T. interdigitale (former T. mentagrophytes-complex). Terbinafine therapy is usually effective in eradicating infections due to these species by inhibiting their squalene epoxidase (SQLE) enzyme, but increasing numbers of clinically resistant cases and mutations in the SQLE gene have been documented recently. Resistance to antimycotics is phenotypically determined by antifungal susceptibility testing (AFST). However, AFST is not routinely performed for dermatophytes and no breakpoints classifying isolates as susceptible or resistant are available, making it difficult to interpret the clinical impact of a minimal inhibitory concentration (MIC). SUMMARY: PubMed was systematically searched for terbinafine susceptibility testing of dermatophytes on October 20, 2020, by two individual researchers. The inclusion criteria were in vitro terbinafine susceptibility testing of Trichophyton (T.) rubrum, T. mentagrophytes and T. interdigitale with the broth microdilution technique. The exclusion criteria were non-English written papers. Outcomes were reported as MIC range, geometric mean, modal MIC and MIC50 and MIC90 in which 50 or 90% of isolates were inhibited, respectively. The reported MICs ranged from <0.001 to >64 mg/L. The huge variation in MIC is partly explained by the heterogeneity of the Trichophyton isolates, where some originated from routine specimens (wild types) whereas others came from non-responding patients with a known SQLE gene mutation. Another reason for the great variation in MIC is the use of different AFST methods where MIC values are not directly comparable. High MICs were reported particularly in isolates with SQLE gene mutation. The following SQLE alterations were reported: F397L, L393F, L393S, H440Y, F393I, F393V, F415I, F415S, F415V, S443P, A448T, L335F/A448T, S395P/A448T, L393S/A448T, Q408L/A448T, F397L/A448T, I121M/V237I and H440Y/F484Y in terbinafine-resistant isolates.

Identification of cutaneous fungi and mites in adult atopic dermatitis: analysis by targeted 18S rRNA amplicon sequencing.

BACKGROUND: Atopic dermatitis (AD) patients have an altered skin bacterial community, with an abundance of Staphylococcus aureus associated with flares, highlighting that microbial organisms may be important for disease exacerbation. Despite strong evidence of association between bacterial skin colonisation and AD, very limited knowledge regarding the eukaryotic microbial community, including fungi and ectoparasites, in AD exists. In this study, we compared the skin and nasal eukaryotic microbial community between adult AD patients (n = 55) and non-AD healthy controls (n = 45) using targeted 18S rRNA amplicon sequencing. Analysis was based on the presence or absence of eukaryotic microorganisms. RESULTS: The cutaneous composition of the eukaryotic microbial community and the alpha-diversity differed significantly between AD patients and non-AD individuals, with increased species richness on AD skin. Alpha-diversity and beta-diversity were similar on lesional and non-lesional skin of patients. The ectoparasite Demodex folliculorum and the yeast Geotrichum candidum were significantly more prevalent on the skin of AD patients. The prevalence of D. folliculorum on lesional skin was greater among patients recently treated with topical corticosteroid. Malassezia was one of the most frequently detected genera at all sites, with M. globosa and M. restricta being the most prevalent. M. restricta was under represented in the anterior nares of AD patients as compared to the non-AD control population. CONCLUSION: Significant differences in the eukaryotic microbial communities were found between AD patients and non-AD individuals, with the most striking finding being the significantly overrepresentation of D. folliculorum on AD skin. Whether D. folliculorum can contribute to skin inflammation in AD needs further investigation.

Photodynamic therapy: A treatment option for terbinafine resistant Trichophyton species.

BACKGROUND: Terbinafine is a first-line agent against Trichophyton-infections. However, treatment failure and resistance due to squalene epoxidase (SQLE) alterations are increasingly being reported. Photodynamic therapy (PDT) is based on combining a photosensitizer, light and oxygen to create photo-activated reactive oxygen species. It has demonstrated in vitro and in vivo activity against various microorganisms including dermatophytes. We investigated if PDT is equally effective against terbinafine resistant and susceptible strains. METHODS: Minimum inhibitory concentrations (MIC) of methylene blue (MB)-PDT against wildtype and resistant Trichophyton rubrum and Trichophyton interdigitale were determined in duplicate in microtitre plates following EUCAST E.Def 11.0 reference methodology. Included mutants harboured F397L, L393F, L393S, F415S or F397I SQLE-alterations. Illumination with red diode light was performed after <3 min, 30 min and 3 h of incubation, respectively, and plates were cultured at 25 °C for 5 days. Geometric mean MICs and MIC ranges were calculated for each isolate. RESULTS: MB-PDT led to complete inhibition of all isolates at geometric mean concentrations of 1-16 mg/L. Efficacy was independent of incubation time prior to illumination, terbinafine susceptibility (MICs ≤0.004-4 mg/L) and presence of SQLE mutations. However, the MB-PDT MIC was slightly elevated (MB: 2-8 mg/L and 8-16 mg/L) in isolates from two pigmented cultures of Trichophyton interdigitale (one wildtype and one harbouring L393F) with a darker color when compared to unpigmented cultures (MB: 0.5-4 mg/L). CONCLUSION: Terbinafine resistant and susceptible strains are equally susceptible to MB-PDT. Lower efficacy was observed against dark coloured isolates which we speculate may be due to melanisation interfering with photo-activation due to preferential light absorption.

[Intense pulsed light treatment for hidradenitis suppurativa: a within-person randomized controlled trial]. / Intense pulsed light treatment for hidradenitis suppurativa: a within-person randomized controlled trial.

BACKGROUND: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease of the intertriginous areas. HS affects hair follicles causing perifollicular inflammation, resulting in the formation of nodules and painful abscesses. Intense pulsed light (IPL) uses selective photothermolysis to destroy the hair follicles. OBJECTIVES: To evaluate the effect of IPL hair removal as treatment for mild-to-moderate HS. MATERIALS & METHODS: We conducted a single-blinded, clinical randomized trial with patients with Hurley Stage I-II. Patients with symmetrical disease were randomized to monthly unilateral treatment of the axilla or groin. The contralateral side served as internal control. Concomitant treatment modalities for HS were not permitted throughout the study. Efficacy was assessed using Hidradenitis Suppurativa Clinical Response (HiSCR), modified Sartorius score (MSS) and patient-reported outcomes. RESULTS: A total of 17 patients completed the trial and were included in the analysis. HiSCR was not evaluated in patients without abscesses or inflammatory nodules pre-treatment. HiSCR was insignificantly different between the intervention side (8/12) and control side (4/10), P=0.467. There was, however, a significant reduction in regional MSS on the intervention side with a median score decreasing from 8.5 (IQR: 6.3-13.5) to 4.5 (IQR 1.8-8.0) post-treatment, P=0.006, and an insignificant score reduction in the control side from 6.0 (IQR: 4.5-8.3) to 5.0 (IQR: 2.5-9.0), post-treatment P=0.492. CONCLUSION: IPL hair removal resulted in a significant reduction on MSS on the treated area with no significant reduction on the control side. Our study suggests that IPL may be an effective treatment for mild-to-moderate HS.