Are you certain that the fungal infection is completely gone? That’s the most common cause. If you have any leakage that leaves the area wet then it’s hard to get rid of fungus.

Yeast infections can be persistent/recurring if they are not fully eradicated from the get go.  Have you ever been prescribed an oral antifungal medication such as Diflucan?  If not, this is definitely something to look into. Calmoseptine - or any topical ointment - may temporarily relieve the itch, but if not used correctly, can actually cause a rebound affect as the damp environment created underneath  the barrier cream can encourage fungal growth. You can mitigate this by ensuring the area is completely clean and dry before applying the barrier cream.  There are over the counter antifungal creams you can try as well; these are mostly sold in the feminine hygiene aisle.  Others here have recommended using Head and Shoulders or another anti-dandruff shampoo as a body wash for maintenance, as these contain antifungal ingredients.  Ensuring you are fully dry after showering also helps.  Hope you can get it sorted!