US blogger Perez, 36, announced this week that he has welcomed another child, and Katie, 40, was quick to comment on the news.
She tweeted: "Holy crap, someone gave @PerezHilton another egg? There are some pretty negligent chickens out there."
But her former Celebrity Big Brother housemate lashed out, labelling her a rubbish parent.
He fumed: "I've seen photos of your kids. You can tell in their eyes that they're lacking in love. You're clearly a sh_t mom Sh_t human!"
Perez's comments come after mum-of-three Katie admitted social services had contacted her over concerns for her children.
She told Management Today: "I did have a call the other day from part of social services that they were concerned about the welfare of my children based on my Twitter feed, which someone thought might be damaging them.
"They said they had to call to follow up."
But Katie insisted her children aren't bothered by her controversial ways.
She said: "They still see it as quite cool I am on TV. Some kid said to them that 'their mum hates your mum'.
"My daughter explains it as 'you just speak your mind mum, and not everyone likes your mind'."