Eight-month-old Jesus Chaparro has brown eyes, brown hair and, sometimes, a blue arm.
"Puffy, like a blueberry -- that's what it looked like," said his mother, Alicia Chaparro.
Chaparro said her son's arm started turning blue a few weeks ago. At first the family thought the baby was having an allergic reaction, but the arm started puffing up, alarming Chaparro.
"It looked like it was going to blow up," she said. "But he wasn't in any pain. He kept looking at it, like it was tingling or something."
The boys left arm turned blue a few times a week, Chaparro said. Pictures show the color change from the fingers, all the way to his mid-arm. The color stops mid-shoulder, almost making the color change look like a blue tan line.
After a series of tests, she was referred to Children's Medical Center in Dallas.
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The mom watched as doctors did an MRI, x-ray, CT scans, even blood and urine test. But they couldn't figure out what was turning it blue, then purple.
Chaparro says her son hasn't hurt himself in the last few weeks, and she insists she hasn't hit the child. The young mother just wants doctors to figure out what's wrong with the arm so they can make it better.
"I worry," she said. "I'm just like, 'What am I going to do? I need some help.'"