Hi Dana, welcome!  Are you seeing an OB-GYN for this situation?  Here's the prescribing info (PI) on Evista, and I can't find any mention of this side effect.  I would check with your OB-GYN and a Gastroenterologist to see why you are having this allergic reaction.  Some people just develop milk allergies...I did and it wasn't from anything I was taking.  It started just after I had my gallbladder removed, and my pcp told me... this is a common side effect from having this organ removed.  Unfortunately, no one told me that prior to the surgery, but I was having very painful episodes of gall stones, so I really didn't have a choice about removing it.

Read through the PI above and see what you can find.  I don't think the Evista has anything to do with this-just my opinion.  The half-life (amount of time it takes for 1/2 of the drug to leave your system) is 15.8 to 86.6 hours, according to the manufacturers Pharmacokinetic Parameter Testing.

Best of luck to you, and I hope you find a resolution to both of these medical issues!