Could possible be a mixture of thrush and nappy rash. Maggie had something similar and it took a number of creams in combination to fix it and I washed after every poo, not just wiped.

3 times a day (morning, midday and night time nappy)
  • Layer of canesten, topped with Desitin (strong zinc based nappy cream)

Other times
  • Bepanthen


All creams had some different element about them that helped with either the thrush or nappy rash. There is a zinc cream combined with antifunal (Daktoxin?) You could try that. HTH