Hi, my sister had the same problem. its more than likely because of the steam from showering.she had to scrape off the paint and sealed it with stuff she got from B&Q and used bathroom paint, but once you take the present paint off allow the bathroom to dry out as best you can, and open window while using the bathroom, keep shower curtain (if you have one) open until steam has cleared then close curtain to allow that to dry. Hope this helps.
nors, October 2012