Best shower filters for eczema or skin irritation

Hi all, can anyone recommend any good shower filters for skin conditions?

Our daughter is 15 months old and seems to get irritated skin/rashes after showering at home. We live close to the city, so I’m not sure if there is something different in the water compared to the outer suburbs of Perth. She has mild eczema which flares up from time to time.

We travel quite often, and every time we go away her skin clears up really well. Then when we come back home, it flares up again after showers, which makes us think it could be something in our water.

We’re not looking for a whole-home filtration system, just something we can attach to the shower head or shower hose. Has anyone had a similar experience or found a shower filter that helped with eczema or sensitive skin?

Any recommendations or advice would be greatly appreciated. Thanks!