sweat

I was out with friends over the weekend and one of my girlfriends called me into her room Sunday morning and showed me her sheets and her washcloth. They were covered in what I thought was blue dye. She told me her underarms, private area and fingernail sweat blue. I have never seen anything like this. This is real. I am not making this up. I was very scared for her. Blue is not a normal color for your body to produce. What is causing this? She told me its the second time its happened to her. I told her to see a medical doctor right away. Do you know what this is? The sheets were colored blue like her sheets were blue, blue on her body and on the wash cloth.