Baby reacting to new huggies nappies

Iv been using huggies and huggies gold both gave me absolute joy however, recently opened a pack of the red huggies. It states new on the top corner. Iv had to stop it as from the day I started using it my baby developed a bad rash. She's 4.5months and has never had a rash. Used them for a week and her nappy area is red and rashy and peeling. Pead said it looks like a reaction to her diapers. Is there something different being used in the "new" pack? Please help as I am getting no response from customer care .