We thank Dr Brady for his response 1 to our article on surgical plume in dermatology, 2 and note his interest in investigating the difference between positive room air pressure compared with a normal pressure room. 1 In a positive air pressure room, the room is sealed and the air pressure in the room is greater than that outside, potentially pushing infectious particles such as those found in the surgical plume away from the patient and operator. 3 In our paper, we discussed the use of high-efficiency particulate air (HEPA) and ultra-low particulate air (ULPA) filters. 2 A HEPA filter can filter particles ≥ 0.3 lm in size, and ULPA filters can filter 99.99% of particles ≥ 0.12 lm. 4 In our research, we found that particles < 5 lm have the capacity to reach the terminal bronchioles. 2 The combination of a positive pressure room with HEPA and ULPA filters could have the potential to reduce the infectious and malignant capabilities of the surgical plume by facilitating both mechanical filtering as well as suction. 2 This warrants further investigation to improve safety outcomes for both patients and clinicians. In the absence of positive pressure rooms (as is the case for many dermatologists), such particulate air filters, measures to reduce the generation of surgical smoke, and provision of appropriate personal protective equipment for patients and staff should mitigate the risk posed by surgical smoke.

HLA-B*13:01 allele has been identified as the genetic determinant of dapsone hypersensitivity syndrome (DHS) among leprosy and non-leprosy patients in several studies. Dapsone hydroxylamine (DDS-NHOH), an active metabolite of dapsone, has been believed to be responsible for DHS. However, studies have not highlighted the importance of other genetic polymorphisms in dapsone-induced severe cutaneous adverse reactions (SCAR). We investigated the association of HLA alleles and cytochrome P450 (CYP) alleles with dapsone-induced SCAR in Thai non-leprosy patients. A prospective cohort study, 16 Thai patients of dapsone-induced SCARs (5 SJS-TEN and 11 DRESS) and 9 Taiwanese patients of dapsone-induced SCARs (2 SJS-TEN and 7 DRESS), 40 dapsone-tolerant controls, and 470 general Thai population were enrolled. HLA class I and II alleles were genotyped using polymerase chain reaction-sequence specific oligonucleotides (PCR-SSOs). CYP2C9, CYP2C19, and CYP3A4 genotypes were determined by the TaqMan real-time PCR assay. We performed computational analyses of dapsone and DDS-NHOH interacting with HLA-B*13:01 and HLA-B*13:02 alleles by the molecular docking approach. Among all the HLA alleles, only HLA-B*13:01 allele was found to be significantly associated with dapsone-induced SCARs (OR = 39.00, 95% CI = 7.67–198.21, p = 5.3447 × 10−7), SJS-TEN (OR = 36.00, 95% CI = 3.19–405.89, p = 2.1657 × 10−3), and DRESS (OR = 40.50, 95% CI = 6.38–257.03, p = 1.0784 × 10−5) as compared to dapsone-tolerant controls. Also, HLA-B*13:01 allele was strongly associated with dapsone-induced SCARs in Asians (OR = 36.00, 95% CI = 8.67–149.52, p = 2.8068 × 10−7) and Taiwanese (OR = 31.50, 95% CI = 4.80–206.56, p = 2.5519 × 10−3). Furthermore, dapsone and DDS-NHOH fit within the extra-deep sub pocket of the antigen-binding site of the HLA-B*13:01 allele and change the antigen-recognition site. However, there was no significant association between genetic polymorphism of cytochrome P450 (CYP2C9, CYP2C19, and CYP3A4) and dapsone-induced SCARs (SJS-TEN and DRESS). The results of this study support the specific genotyping of the HLA-B*13:01 allele to avoid dapsone-induced SCARs including SJS-TEN and DRESS before initiating dapsone therapy in the Asian population.

Background Acne is one of the most common skin problems among human populations. A facial cleanser formulated with alkyl ether carboxylate (AEC) and alkyl carboxylate (AC) can improve acne by cleansing sebum on facial skin but cannot effectively remove keratotic plugs in the skin pores. Recently, we confirmed that Tris (hydroxymethyl) aminomethane and L‐arginine (Tris/Arg) is able to reduce sebum levels, disrupt keratotic plugs in vitro and decrease pore size on facial skin. Objective To compare the efficacy of the Tris/Arg‐formulated cleanser with the AEC/AC cleanser in Thai subjects with acne. Methods We designed a randomized, double‐blind, controlled, parallel trial. Thirty‐four male Thai subjects with mild to moderate acne were assigned to one of two groups: one group used the Tris/Arg cleanser while the other used the AEC/AC‐based cleanser twice a day for 4 weeks. Results After 4 weeks, significant decreases in noninflammatory acne were observed in both groups, yet significant decreases in inflammatory acne were only observed in the Tris/Arg cleanser group. The sebum level prior to and 30 minutes after facial washing showed no change in either group. The average pore size with keratotic plugs on the cheeks was significantly decreased in the Tris/Arg group. More than half of subjects in both groups observed acne improvement but more subjects in the Tris/Arg group noted pore size improvement. Conclusion The Tris/Arg formulated cleanser has a high efficacy for significantly reducing both noninflammatory and inflammatory acne accompanied by decreases in pore size with keratotic plugs in male Thai subjects.

Herpes simplex virus (HSV) and varicella zoster virus (VZV) are the most common causes of viral vesicular dermatoses of the skin and mucous membranes (1). Tzanck smear is widely used as a bedside test for herpetic skin infections (1-3). It is performed using skin scrapings and traditionally involves Giemsa stain. Depending on the protocol, the multiple steps of staining, fixation, and washing usually require 15-60 min (4-7). Therefore, it is not always practical to perform this very useful test due to time constraints. Methylene blue (MB) is an alternative and available blue dye (4). There are few reports regarding its use for Tzanck testing as a rapid technique (4,8,9); however, to our knowledge, no clinical studies have examined the diagnostic value of MB in the Tzanck smear. In this study, we evaluated the utility of MB in terms of its potential non-inferiority to the conventional Giemsa stain in the diagnosis of herpesvirus skin infections. The study was designed as a cross-sectional analytical study. The protocol was approved by the local institutional review board (No. 674 59) and the trial was registered with clinicaltrials.gov (Identifier: NCT03178747). Written informed consent was obtained from each patient prior to participation in the study. The inclusion criteria were patients over 18 years of age with suspected HSV and VZV skin lesions. Negative control cases comprised patients with other vesiculobullous eruptions (e.g., acute eczema). Specimens obtained from the lesions were smeared onto 2 different glass slides and allowed to air-dry. Subsequently, 1 slide was stained with MB and the other with Giemsa. MB staining was achieved by putting 2-3 drops of MB solution (Merck KGaA, Darmstadt, Germany) onto the glass slide. No washing was needed and the cover slip was then placed. Final concentration of MB was 1.4 mg ml (10). The entire staining process lasted approximately 10-15 s. In contrast, the Giemsa stain was performed using Giemsa solution (Merck KGaA) (11), but the specimen was not fixed. The slide was immersed in the solution and left for