Allergic reaction to formula?

[TwistTee]

As if I do not feel bad enough for introducing formula for the first time to my 4 month old last night, he has woken up with constipation and is covered in red hive like blotches. It looks like some sort of allergic reaction to the formula, Aptimil.
I am waiting for the surgery to open to take him in. No breathing difficulties so I do not think it is an emergency, but I am watching him closely just in case.
Has anyone experienced this?

Not experienced it myself but have seen it on here before. Hope all goes well at the GPs.

Good luck at the drs

Just wanted to say when I put my ds on formula we didn't get on with Aptamil either it would basically run straight through him and we were getting 9 explosive nappies a day.

We changed the formula to cow and gate and after about 10 days all back to normal.

Just got back from th GP. She recommended a low dose of Piriton for today and changing the formula, but otherwise she was happy with my ds. Thanks for the replies.