A hotel guest complained that she was allergic to bed sheets. How to handle complaints?

Through what channels to complain! If this problem hasn't happened before, the first thing to confirm is whether the bedding and sheets of the day have been cleaned and disinfected, so that ordinary hotels can handle them with the washing company. Please make sure that if you don't have any problems, it may be his own skin problems, so don't worry. On the contrary, the sheets and sheets he slept in should be treated specially.