Looking back at old photos, Justin Hayden can see the difference in his 5-year-old daughter’s face.In those Christmas photos from 2016, Gwenyth’s long, golden hair framed puffy cheeks. The glands in her neck were swollen, too, from what Hayden believed was a lingering cold.“It was so gradual that, at the time, I didn’t notice it,” Hayden said.Now, a year after then-4-year-old Gwenyth was diagnosed with leukemia, Hayden can see physical toll cancer was inflecting on his youngest daughter.It all started with a seemingly harmless cold.Gwenyth caught a cold in early December 2016. She seemed to get a little better, only to get knocked down by the bug again. On Christmas Day, a typically energetic Gwenyth was tired and lethargic. She spent most of the day snuggled on her dad’s chest, sleeping while her cousins played. That’s also when Hayden discovered bruises all over Gwenyth’s body — bruises she couldn’t remember getting.A trip to urgent care resulted in a sinus infection diagnosis and an antibiotic prescription. When Gwenyth’s health failed to improve, she was given a stronger antibiotic.Finally, after a snowstorm that closed the pediatrician’s office, Gwenyth got in to see her doctor. He immediately sent her to Randall Children’s Hospital at Legacy Emanuel Medical Center in Portland.“As soon as they looked at her, they knew what it was,” Hayden said.Gwenyth was diagnosed with acute lymphoblastic leukemia — a cancer of the blood and bone marrow, in which the bone marrow makes too many immature white blood cells. It’s the most common type of cancer in children, adolescents and adults younger than 20, according to the Leukemia and Lymphoma Society.