Hi Doctor. My Baby Always Scratching Her Eare Even In

Hi doctor. My baby always scratching her eare even in her sleep. Her GP said she was fine, I went for a second opinion to her paediatrician and she said her ears looked fine. That was within the first two weeks that I noticed the pattern of scratching. It's now been over two months and something is definitely irritating her ears. Could it be the nan 3 formula. She is 18 months old.