Need some help with diagnosing this diaper rash. My son is 6 weeks old... about 2 weeks ago he started getting a rash that was small red sores around his anus. I tried treating with Penaten with no luck. After a few days switched to Canesten. No improvement, so saw the pediatrician who gave us prescription for Nystatin. 2 days and still no improvement - and then it got worse and he was crying for a full day and his bum looked chapped.

I took him to my GP who basically just said "ya it could be yeast. Just keep using the cream and it will get better eventually". I bought Desitin and put that on, and I think it really hurt him, but it cleared it up after 2 changes. I gave up on the Nystatin because it didn't seem to be helping and it didn't look like yeast, in my opinion. Since then, we have been using Desitin and Vaseline at every change, changing him often (no more than 2 hours or right away if he poops), and he gets diaper free time twice a day. I am struggling with oversupply and I thought I had figured out that the problem is his poops are too acidic and are irritating his skin. Now today - his bum looks like this again (see picture). Any ideas or advice for me? Thank you.