RESUMEN
BACKGROUND: Patients with atopic dermatitis (AD) have increased susceptibility to irritants. Some patients have questions about types of water for bathing or skin cleansing. OBJECTIVE: We studied the pH of water from various sources to give an overview for physicians to recommend patients with AD. METHODS: Water from various sources was collected for measurement of the pH using a pH meter and pH-indicator strips. RESULTS: Bottled drinking still water had pH between 6.9 and 7.5 while the sparkling type had pH between 4.9 and 5.5. Water derived from home water filters had an approximate pH of 7.5 as same as tap water. Swimming pool water had had pH between 7.2 and 7.5 while seawater had a pH of 8. Normal saline and distilled water had pH of 5.4 and 5.7, respectively. Facial mineral water had pH between 7.5 and 8, while facial makeup removing water had an acidic pH. CONCLUSION: Normal saline, distilled water, bottled sparkling water and facial makeup removing water had similar pH to that of normal skin of normal people. However, other factors including benefits of mineral substances in the water in terms of bacteriostatic and anti-inflammation should be considered in the selection of cleansing water.