Can I use nappy rash creams?

Yes, you can. However, there are some rules about which ones you should use, and what changes you may need to make to your routine.

You need to avoid using petroleum or zinc based creams unless you are using a nappy liner. These types of barrier creams contain oils that seep into the fibres of the absorbent layers of the nappy, making them less absorbent over time. You can do a strip and sanitise to remove the oils from the fabrics if you find you are having this issue (see: https://cleanclothnappies.com for S and S information). Clean Cloth Nappies state that with a correct wash routine, all nappy rash creams will wash out of nappies. Plant-based/sensitive/eco detergents will not be as effective as mainstream detergents.
If you are not using a nappy liner, then you can use non-petroleum/zinc based creams and balms. Consider some of the options pictured below.
If you are experiencing recurring nappy rash, consider making some changes to your wash routine, such as switching to a different detergent, or changing nappies more regularly. Always seek medical advice for recurring nappy rash, as there may be an underlying cause that needs to be addressed.