为什么冬天洗澡皮肤容易痒？
人体皮肤最外层是角质层，上面有一层酸性皮脂膜，皮脂膜中的脂肪酸、尿素、尿酸、乳酸盐对皮肤有着保护和滋润作用。
The outermost layer of human skin is the stratum corneum, on top of which there is an acid sebaceous film. The fatty acids, urea, uric acid and lactate in the sebaceous film protect and hydrate the skin.
据科普中国介绍，冬季天气寒冷，空气干燥。人体皮脂腺、汗腺分泌的汗液减少，皮脂膜也明显变薄。
皮脂膜最怕经常性的碱性刺激和高温破坏，如果频繁洗澡和大量使用沐浴液，就会使肌肤上正常的角质细胞过多脱落，皮脂膜也会变得更薄，进一步导致保护皮肤的屏障破坏，引起皮肤干燥瘙痒和皮屑加重。
冬季多久洗一次澡比较合适？
对于年轻人来说，冬天2-3天洗一次澡为宜，老人和婴幼儿建议3-5天洗一次，尽量少用清洁产品，用清水洗澡即可。
For young people, it is advisable to take a bath once every 2-3 days in winter, and the elderly as well as infants are recommended to take a bath every 3-5 days. Use cleaning products with harsh chemicals as little as possible.
贝勒医学院皮肤病学教授拉贾尼·卡塔（Rajani Katta）建议淋浴后在擦干身体之前可以先用手轻轻地把皮肤拍干，然后使用润肤乳进行保湿。
Dr. Rajani Katta, professor of dermatology at Baylor, recommended patting the skin partially dry, then using moisturizer cream while skin is still damp after a shower.
早上洗澡好还是晚上洗澡好？
很多人说早上洗澡要比晚上好，此种说法对吗？
事实上，什么时候洗澡取决于想达到什么样的效果，可以根据自身需求选择，并没有严格的规定。
早上洗澡会使头脑清醒，元气满满地进入工作状态。而晚上睡觉前来一个温水浴，在清除皮肤表面污垢的同时，还能加快血液循环，使全身肌肉放松，消除疲劳、改善睡眠。
Taking a bath in the morning can be refreshing, helping you feel more alert at work. By contrast, a warm bath before going to bed can remove the dirt from the surface of the skin, accelerate blood circulation, relax the muscles of the whole body, eliminate fatigue, and improve sleep quality.