diarrhea or just frequent poos - Aptamil?

[Niru13]

My 3-week old baby was doing really well on Aptamil for 2 weeks. Over the last couple of days however, she has started doing about 15 bowel movements a day. Although the consistency seems fine for a baby on Aptamil - loose, mustardy type stools - the frequency seems really high to me. Has anyone had experience of this? Is this diarrhea or quite normal? The poos don't smell bad. She also now has pretty bad nappy rash.

I wonder if she is allergic to Aptamil but if so, wouldn't we have seen a reaction earlier?

I would greatly appreciate any input from anyone who might be able to shed some light on this before I consider swapping formulas.

any other symptoms?

No other symptoms. Sleeping and feeding fine. No vomiting.

My ds is now 17 weeks old and at first he had SMA.He had dreadful wind,verging on the borders of colic and would scream for hours.
After about 6 weeks or so someone mentioned changing the milk and I tried Aptamil.He virtually stopped screaming but his nappies were horrendous.Sorry if tmi but they were very watery with what looked like scrambled egg inside and bright yellow.He was also having about 6 a day like this and would need a change of clothes each time as they were so explosive,they came through the nappies.
I phoned Aptamil who said this is normal and for some babies it calms down after about 2 weeks,while with others it stays for the duration.After I finshed the tin I changed him to Farleys instead,as I couldn't bear the nappies and he has been like a different baby.He is now constantly smiling,hardly cries or screams and is sleeping through the night from 9pm-8am.
Obviously every baby is different and it may have just been a coincidence,but I'm glad I changed his formula again and he seems to be thriving on it.

My 3 month old baby was fine for 1 week after I started Aptamil and suddenly he got loose runny stools which would often soil his clothes. Doctors unfortunately misdiagnosed him as lactose intolerant and was started on lactose free diet for 1 month. He started gaining more weight than normal and so i switched Lactogen and guess what he’s doing fine, he wasn’t lactose intolerant he was only allergic to Aptamil.