My daughter is 14months old and she has been having blue/purple tinged skin "spells" for a couple months now. It occurs in her arms, legs, hands, feet, lower face, lips, cheeks (inside and outside cheeks), and a couple times on the skin under her eyes. It is never warmer or colder than usual, she doesnt have any trouble breathing that i have noticed at all, it happens almost every morning during breakfast and last till after. it also happens at other meal times, and sometimes just randomly. Though she is not crying or in any kind of pain when this happens, she is not as active as normal and she does seem "cranky".
I went to her pediatricain 2 times for this and they did a pulse oximetry, which came back normal- though she was not blue at the exact time of them taking it and chest x-ray that looked normal.
they told us go to the ER because they could do no more for us so we did and they seemed dismissive of the blue-ness because she had a cold at the time.