It was just another day at the playground for Dave Fletcher and his three-year-old daughter Izzy when he decided to take a picture of the little girl falling asleep on the swing.

The 39-year-old dad wanted to immortalize an adorable and innocent childhood moment, but little did he know that he captured a scary symptom that her daughter had been living with.

"It was just an afternoon pop out to the swings. She was swinging away "” I turned around and she had dropped off," Fletcher recalled. "She was drowsy and fell asleep but I didn't think much of it. I thought it was a cute moment and just took a picture of her as you do."

Turns out, the tiredness and sleepiness Izzy had been experiencing were all signs of a deadly disease, but the couple chalked it up to less serious illnesses, like a cold.

"It was only afterward we realized it was all part of the symptoms and what I'd captured was her displaying signs of something more sinister," Fletcher explained. "She had been tired, had had a few colds or viruses, and quite a bit of bruising on her legs. But we put all this down to normal childhood bumps and minor illness."

Just a few weeks after the photo was taken, Fletcher and his wife Vicky, 37, were given a news no parent ever wants to hear - their toddler had leukemia.

"When she was diagnosed, it came out of the blue. We were both in real shock as it happened so fast," he said. "It was a big unknown. A family member died of leukemia five years ago, so it was a scary time. We didn't know what was going to happen at that stage or what the future held."

The Fletchers first took Izzy to the hospital after an unusual rash appeared on her leg. They were advised to come back for blood tests if the rash didn't go away or if it got worse after a few days.

However, by morning, Izzy's rash had spread and she developed a high fever, so she needed to be rushed to the emergency room. That same day is when she received the cancer diagnosis, and was scheduled to begin chemotherapy the following week.

Izzy has since undergone 570 doses of grueling chemo, and is enrolled in a clinical trial until May 2019.

"It makes us more optimistic. She doesn't have to have so many steroids because of the trial she is on," Fletcher explained. "It's a treatment plan they use in other countries and we are grateful to be given the opportunity. It shows just how important research is in pioneering new treatments."

Even through the intense treatments and setbacks, the family is thankful that Izzy's illness was caught early enough, and that the "type of leukemia she has has a better chance of recovery than some others."

The couple are now sharing Izzy's story to warn other parents about sneaky cancer symptoms in small children. Although some of these symptoms will not manifest in some ill kids, there are some tell-late signs that you should always watch out for.

In the case of leukemia, fatigue is the most common symptom that patients of all ages experience, but being that it is a sign of several other conditions, many won't connect the dots right away.

Share Izzy's story with family and friends who have young kids to spread awareness.