Transepidermal Water Loss after Water Immersion

Objective: To observe changes in transepidermal water loss (TEWL) at different times after water immersion. Materials and Methods: TEWL values were measured before water immersion and at 3, 5, 10, 15, 20, and 30 minutes after immersion of the skin in water for 5 minutes. Results: Forty-one healthy volunteers were enrolled with an average age of 30.4±5.5 years. Twenty-five subjects were female and sixteen were male. The TEWL value before water immersion (TEWLbaseline) was 13.16±7.27 g/m2/h and TEWL values at 3, 5, 10, 15, 20 and 30 minutes after immersion were 23.21±7.67, 16.12±3.42, 14.76±6.36, 14.45±6.67, 13.53±4.67 and 12.96±5.18 g/m2/h, respectively. After immersion, TEWL values at 3 and 5 minutes statistically increased compared to TEWLbaseline (p<0.001). TEWL values between 10 to 30 minutes gradually dropped with no statistically significant difference compared to the previous period and TEWLbaseline. Although total water loss from the skin occurred within 30 minutes, 56.9% of it occurred within 10 minutes after immersion. There was no significant difference between TEWLbaseline in males and females but the TEWL values at 3, 5 and 15 minutes after immersion in males was higher than in females (p<0.05).  Conclusion: TEWL statistically increased after water immersion for only 5 minutes. The cumulative percentage of TEWL was high within 10 minutes. Gender did not affect TEWL values before immersion; however, males experienced more water loss from the skin than females after immersion. Therefore, moisturizer should be applied immediately before TEWL occurs

Prevalence and Trend of Photodermatoses in Thailand: A 16-year Retrospective Study at Siriraj Hospital

Objective: Photodermatoses are a group of cutaneous disorders with abnormal reactions triggered by exposure to sunlight. Previous studies reported varying photodermatoses prevalence in Caucasians and African-Americans; however, it was seldom reported in the Asian population. The aim of our study was to determine the prevalence, clinical characteristics and trend of photodermatoses in Thailand. Materials & Methods: A retrospective chart review was performed at the Faculty of Medicine Siriraj Hospital, Mahidol University using diagnoses from the International Classification of Disease (ICD), Tenth Revisions codes, between January 2005 and September 2021. Results: A total of 561 patients with definite diagnosis of photodermatoses were identified. The prevalence of photodermatoses in the outpatient dermatology clinic was 3 cases per 1,000. The most common photodermatoses was chemical and drug-induced photosensitivity (39.4%), followed by immunologically-mediated photodermatoses (30.1%), photo-aggravated dermatoses (29.4%) and genophotodermatoses (1.1%). Overall phototesting was performed in 276 cases (49.2%). In our study, some photodermatoses had unique clinical characteristics including pinpoint popular variant of polymorphous like eruption and adult-onset actinic prurigo. Over 16 years, the trend of patients being diagnosed with photodermatoses has continued to rise gradually with an increment of 1.67 times. Conclusion: Photodermatoses are uncommon in Thailand. Some photodermatoses have distinctive clinical features in Asian populations. The trend of photodermatoses in Thailand is continually rising, reflecting an increase in physicians’ awareness and knowledge of these cutaneous conditions