What can this be ?


My daughter (5 months) seems to always break out on her back every time we take her outside or if she’s in her car seat for more than 30 mins , seems she gets it more when she sweats but what can be causing it. ? Her doctor doesn’t know what it is and he just gave her Hydrocortisone 1%

I’ve washed all her clothing and the car seat cover twice and we use baby dreft stage 2