One parent has issued a warning after their son's pains and rash ended up being much more serious than they were initially told by doctors.
Mum-of-five Jessica Cooke, from Middleton, says she went to run a bath to help her son Harvey, who is autistic, to help with his severe back and leg pains.
The 16-year-old had been taking medication that was prescribed by a doctor to help with the pains after being told that his 'muscles were tight' - but nothing seemed to work.
Within a few days, the pain had escalated and he was struggling to walk properly.
And his parents knew that something was instantly wrong, despite Harvey having a high pain threshold - not even shedding a tear when he broke his arm as a young child, report Manchester Evening News.
The mum says she could see her teenage boy was clearly 'in agony'.
Following this, Jessica says she took Harvey to Oldham Hospital's A&E department on February 9, where a doctor 'felt his back' and said Harvey's 'muscles were tight', but only prescribed him diazepam.
However, the pain would not pass and it became completely 'unbearable' to the point where Harvey was left crying in his room at night.
Concerned mum-of-five Jessica, who is a nurse, ran him a warm bath to try and soothe the pain, when she noticed he had a rash on his feet that had spread to his arms.
She said: "As he came out of the bath he noticed a rash coming on his arm and said he had it on his feet. All I could describe it as was speckly, like burst blood vessels where the blood comes to the surface of the skin.
"We had taken him to A&E because it had escalated to the point where he couldn't walk. He was in absolute agony."
Days later, on February 14 - after struggling to get hold of a GP - Jessica and dad Stuart immediately called 111.
Paramedics arrived at the house and took Harvey back to A&E at Oldham, where he was given morphine to help cope with the extreme pains he was suffering and had turned very pale.
It was at this crucial point that a consultant made the decision to take some blood tests from Harvey.
His family could never have predicted the devastating news they were about to receive.
Jessica said: "They came back in straight away and told us it was Leukaemia.
"It was horrendous. His dad was with him and I was at home. When they phoned me to tell me I remember just screaming. I broke down.
"We couldn't believe it. I couldn't wrap my head around it or process what was going on at first. Then I got my nurses head on and asked straight away what the next steps were."
Harvey was transferred to Royal Manchester Children's Hospital that same day.
Further tests revealed that the teenager had Acute Lymphoblastic Leukaemia (ALL), a type of blood cancer that starts from white blood cells called lymphocytes in the bone marrow. It typically develops quickly over days or weeks and is the most common type of leukaemia to affect children.
Explaining how she felt, the mum-of-five said: "In my head, I just knew we were going to get the worst news from those results, which we did. Within the day they were telling us the treatment plan for Harvey."
From February 15, a four-week long treatment of gruelling and intensive chemotherapy commenced as part of the induction stage, with Harvey now taking three lots of medication each week, with Jessica saying: "They are going to essentially blast him with the chemotherapy. It's absolutely horrendous.
"He has become nauseous, lethargic, and is hardly eating anything. It totally weakens his whole immune system."
"Harvey's autism shines through but he's very high functioning. Everybody that meets him just calls him amazing. He is usually so bubbly. Even when he came into the hospital he was apologising for being poorly and thanking everyone. He is an amazing son."
Doctors will review how Harvey is responding to the treatment and he will remain bedbound in hospital for weeks. The experience has prompted Jessica to warn other parents about the symptoms.
The mum continued to say: "Harvey could be stuck there for months, it all just depends on how his body reacts, although because of his age, they do generally have positive outcomes.
"I've got four other children, so we are juggling that at the moment too, whilst also wanting to be here with Harvey constantly.
"It's an absolute whirlwind, an emotional rollercoaster, but from going through this we know how important it is to not just accept the first answer you're given if you feel something is wrong.
"Especially because children and teenagers have falls or bumps all the time, but it could still be something sinister. My fear is other teenagers could present with these pains and not know they are at risk. They just need a simple blood tests to get the answers and rule it out."
Family friends have since launched a fundraising page to help raise money for the family, with nurse Jessica now taking time off to care for Harvey.
You can donate to the fundraiser here.
The Northern Care Alliance, which manages Oldham Hospital, has been contacted by the Mirror for a comment.
