Peroxisome proliferator-activated receptor γ (PPAR-γ) is a ligand-activated nuclear receptor that regulates the transcription of various genes. PPAR-γ plays roles in lipid homeostasis, sebocyte maturation, and peroxisome biogenesis and has shown anti-inflammatory effects. PPAR-γ is highly expressed in human sebaceous glands. Disruption of PPAR-γ is believed to be one of the mechanisms of primary cicatricial alopecia (PCA) pathogenesis, causing pilosebaceous dysfunction leading to follicular inflammation. In this review article, we discuss the pathogenesis of PCA with a focus on PPAR-γ involvement in pathogenesis of lichen planopilaris (LPP), the most common lymphocytic form of PCA. We also discuss clinical trials utilizing PPAR-agonists in PCA treatment.

Background. Ashy dermatosis (AD) and lichen planus pigmentosus (LPP) are both acquired macular pigmentation of uncertain aetiology. Despite the controversy surrounding their entities, recent global consensus has concluded that they are 2 different diseases with distinct clinical presentations. Nevertheless, there are limited data on their histopathological comparisons. Objective. To evaluate the differences in histopathological findings between AD and LPP. Methods. Electronic records and photographs of patients with the diagnosis of AD or LPP from January 2008 to December 2018 were retrospectively reviewed by a dermatologist. Patients were then classified into groups with AD and LPP, based on the clinical descriptions from the recent consensus. Those with history/clinical presentations suggestive of other causes of macular pigmentation were excluded. The histopathological diagnosis of AD and LPP was then reevaluated by a blinded dermatopathologist. Results. One hundred and twenty-four patients with acquired macular pigmentation were identified; 24 were excluded due to clinical history or photographs being inconsistent with AD or LPP. Of the remaining 100 patients, 71 had clinical findings consistent with LPP while 29 had AD. The prevalence of epidermal hyperkeratosis was significantly higher in LPP when compared to AD (33.8% vs. 0%, p<0.001), as well as epidermal hypergranulosis (35.2% vs. 0%, p<0.001), lichenoid dermatitis (49.3% vs. 7.1%, p<0.001), perifollicular infiltration (47.9% vs.10.3%, p<0.001), and perifollicular fibrosis (35.2% vs. 10.3%, p=0.01). In addition, the degree of pigmentary incontinence was more severe in LPP (21.1% vs. 3.5%, p=0.015). For AD, vacuolization of the epidermal basal cell layer was more common (96.4% vs. 77.5%, p=0.02). Conclusions. Although most cases of AD and LPP can be diagnosed clinically, in doubtful cases, histopathological findings of lichenoid dermatitis, epidermal hyperkeratosis/hypergranulosis, and moderate to severe pigmentary incontinence can help distinguish LPP from AD.

For dermatologists, diversities of human races result in an opportunity to encounter patients with various skin types. Cosmetic procedures have gained more popularity and become more accessible over the past decades. Thus, the selection of appropriate treatment protocol for each patient becomes inevitable. This review will focus on basic knowledge and key points in performing safe cosmetic-related procedures in patients with dark-complexioned skin. In terms of structure and function of the skin, people of color have equal epidermal thickness, corneocyte size and melanocyte number. However, they have more stratum corneum compaction, melanosome dispersion and melanocyte activity than fair skin individuals. Data regarding drug penetration and cutaneous irritation showed conflicting results. Superficial chemical peels and microdermabrasion can be done safely in dark-skinned patients. Medium-depth peel should be used with extreme caution. While deep-depth peel should be avoided at all times due to pigmentary and textural complications. Prolonged treatment interval, use of priming agents and sun protection are recommended. Injectable materials including botulinum toxin and soft tissue augmentation by hyaluronic acid filler can be done harmlessly in dark-skinned patients. Lasers and energy-based devices should be done with caution. Higher melanin dispersion and melanocyte activity acts as competitive chromophore. Pigmentary or textural changes can occur after aggressive treatment protocol. High energy setting, pulse stacking, short wavelength lasers and short treatment interval should be avoided in dark-skinned patients.

The smartphone apps provide a user-friendly option for measurement of heart rate (HR) by detecting pulsatile photoplethysmographic signals with built-in cameras from the fingertips, however, the validation study is limited. We compared HR detected by the smartphone apps (App1 = Instant HR, App2 = Cardiio: HR Monitor and App3 = Runtastic HR Monitor) with simultaneous standard ECG monitoring in the adult patients at the critical care unit. HR measurements were obtained from 140 patients with mean age 67.6 ± 15.3 years. Mean baseline HR was 89.1 ± 19.1 bpm (range, 32-136 bpm). Sinus rhythm was presented in 111 patients (79.3%), atrial fibrillation in 25 patients (17.9%), pacemaker rhythm in 3 patients (2.1%), and high-grade AV block in 1 patient (0.7%). The ECG-derived HR correlated well with App1 (r = 0.98), App2 (r = 0.97), and App3 (r = 0.92). In patients with regular rhythm, mean absolute deviation was 0.8 ± 1, 0.7 ± 0.9, 1.0 ± 1.3 bpm on App1, App2 and App3, respectively. In the patients with irregular rhythm, median absolute deviation (IQR) was 3 (2-5.5), 4 (1.5-11.5), and 6 (2-13) bpm. Skin colour did not affect with the HR measurement. HR measurements from all applications were correlated well with ECG monitoring. However, it was less accurate in case of irregular rhythm such as atrial fibrillation. Key messages Several reports on inaccuracy of mobile health apps have been published. We conducted the validation study in the real patients by using popular mobile apps. Heart rate measurements from mobile apps were correlated well with standard ECG. The accuracy of HR from apps was worse at irregular rate and tachycardia.

Background. Vitiligo is an acquired hypopigmentary disorder. The prevalence of vitiligo is 0.1–2% worldwide. Numerous autoimmune diseases are associated with vitiligo, including autoimmune thyroid diseases. The prevalence of thyroid abnormalities is up to 34% in vitiligo patients depending on ethnicities. Objective. This study aims to investigate thyroid abnormalities in Thai patients with vitiligo. Methods. Medical records of vitiligo patients attending outpatient dermatology clinic at a university-based hospital from 2012 to 2016 were retrospectively reviewed. Data regarding vitiligo, clinical features, and autoimmune thyroid laboratory results were retrieved and analyzed. Results. Among 325 vitiligo patients identified, anti-thyroid peroxidase and anti-thyroglobulin were positive in 90 (27.7%) and 63 patients (19.4%), respectively. Positive thyroid antibody was associated with female gender (p<0.001) and vitiliginous hand lesions (p<0.02). Out of 197 patients with complete thyroid function test, the prevalence of autoimmune thyroid diseases (AITD) is 12.7%. Female, nonsegmental type, higher affected area, and the presence of leukotrichia are significantly associated with AITD in vitiligo patients. Conclusions. Prevalence of positive thyroid antibodies and AITD in Thai patients with vitiligo is compatible with previous studies around the world. Screening for AITD with thyroid antibodies and serum TSH is essential for vitiligo patients.

Background: Patient self-assessment is a potential tool in clinical practice to obtain subjective information of acne severity also in clinical trials to assess the general population in research and epidemiologic studies. The patient self-evaluation of acne severity has not yet been developed in Thailand. Objective: We aimed to validate an acne severity grading self-assessment suitable for the Thai population. Methods: A pilot study was conducted in 77 volunteers with acne lesions. We developed the Thai Global Evaluation Acne Scale (TGEA) and Thai Global Acne Grading System (TGAGS) by translating and adapting the original version. Patient self-assessment of acne severity was performed in two rounds. A training session about acne was provided to all participants lesions before starting the second round. Reliability between the self-assessment and clinician assessment of acne severity was statistically assessed. Results: For TGEA, 48.05% participants rated their acne severity corresponded with the clinicians (Cohen’s kappa coefficient, kappa = 0.26). After receiving the training, 79.22% subjects responded their acne severity corresponded with the clinicians (kappa = 0.66). For TGAGS, 77.92% patients who answered their acne severity corresponded with the clinicians (kappa = 0.52). After receiving the training, 94.80% participants responded their acne severity corresponded with the clinicians (kappa = 0.89). For raw score of the TGAGS, the intraclass correlation coefficient (ICC) during the self-assessment of acne severity compared to the clinician assessments was 0.54 and it increased to 0.79 after the training. Conclusion: Due to the almost perfect reliability, we suggested that TGAGS is a reliable subjective self-assessment of acne severity suitable for the Thai population. The training is essential in enhancing the reliability of this instrument. Our study’s findings can facilitate clinical practice and research studies.