We have had everything sprayed numerous times - home and assisted living. There have been no bugs found anywhere. Once there was a beetle on the bathroom floor - a couple of months ago. There was also a gnat that she found one day. The assisted living people are doing all they can but she is the only one complaining - constantly. We have been to the doctor because she insists she has bite marks. They have told her they are old age spots. Has anyone dealt with this? What did you do?
Is there any indication if the perceived bite marks are where specific types of clothing (i.e., with elastic) come in contact with her body, or is it a generalized itching?
If you do her laundry, you could also try changing detergent to something without fragrance and most certainly don't use those toxic dryer sheets.
Perhaps a good auto-immune workup might also be helpful.
In the meantime, ice cubes work for me to calm itchy skin, although it may be uncomfortable for an older person because it does chill the skin. Mint lotion is also helpful, but it needs to be a good organic mint lotion, not something from China.
One thing you can try is buy a skin lotion like Cerave and tell her it will help with the problem. Tell her it is known to moisturize, soothe, and repel bugs. It might help and certainly won't hurt.