My 11 month old granddaughter gets a red rash every time she comes to my house.?

It always starts on the right cheek then spreads to the left cheek. Next to the diaper area, chest and neck. By the second day under her eyes is black and her eye area swells. When she goes home, it's gone in a day and she is left with dry skin only. I have eliminated food and carpet. I can only ume it's environmental Nothing has changed in all the time she has been coming here. She did not get it the first 6 months she was coming here. She was coming every weekend. Now due to the rash she can't come here anymore. Any ideas? I want to start getting her again