Schoolgirls in Preston have been removed from their classes and put in isolation - for wearing socks.
Parents of children at Fulwood Academy say their daughters are being victimised for medical problems, because of strict new rules on wearing tights.
The Academy, which is currently in special measures, brought in a new uniform following the Easter break, requiring female pupils to wear black tights with skirts, or trousers as an alternative.
Principal Philip Grant said the changes were "designed to bring standards back to the school and have already generated positive changes, which is why they must be adhered to at all times."
The mum of one 12-year-old girl, who asked not to be named, said in recent warm weather, tights had caused her daughter to suffer from painful sweat rashes.
Despite approaching the school about the issue, her daughter was today put into isolation for wearing socks.
The mum said: "My daughter takes anti-histamines and her skin is very sensitive. In this recent hot weather, the tights have rubbed and she's got painful, weeping rashes.
"We've been trying barrier cream, but it's not helped. Last night she was struggling to sit down, so I decided that her legs needed to breathe.
"I explained this to the school and why she would be wearing socks, but then I got a phone call to say she's been put into isolation.
"It's a ridiculous situation - they're punishing a child when it's not their fault.
"Considering the school's in special measures, I think they should be concentrating on more important matters."
The mum added: "They say she can wear trousers instead, well they will still rub her where her skin is inflamed. And not everyone has bought trousers. It's unreasonable to expect you to get a new uniform from Moorhouses with such short notice".
A father of a 13-year-old girl said his daughter has been put in isolation five times for not wearing tights - despite them causing painful rash symptoms.
He said: "My daughter has an illness which means she can't wear tights, but the school are not prepared to listen. I've asked to speak to the principal several times, but I'm still waiting to hear from him.
"My daughter has today (Thursday) refused to go into isolation, so I've had to take time off work to pick her up.
"The school has brought in this new rule without any consultation of the parents or pupils, and now it's causing problems for quite a few girls.
"My daughter is being victimised for her medical condition, and enough's enough."
Philip Grant, principal of Fulwood Academy, said: “This is of course a difficult situation, but in the interest of all our students it’s important we maintain a consistent approach with regards to the rules put in place. All our policies have been designed to bring standards back to the school and have already generated positive changes, which is why they must be adhered to at all times.
“Students were found to be frequently flaunting the previous rules in relation to uniform. When I first joined the academy, I received feedback from parents indicating that they and their children would prefer a strict uniform policy; that policy was subsequently put in place and has been welcomed. Female students have two options: knee-length skirts and tights, or trousers.
“I know that a very small minority of parents are concerned about this, and that some are in discussion with members of staff to come to a mutually beneficial agreement in keeping with the school’s uniform policy. During this time, our main focus will continue to be the delivery of quality teaching and learning for our students.”