toddler w/ blue lips

Several times in the past few months, (fall and winter)I have noticed that my son's lips will turn blue, and the area around his mouth will turn pale blue/white. His lips also will get cold when this happens.  This will happend when he wakes up, or some other time during the day.  Doctors can find nothing wrong when they check his oxygen level, and hear nothing wrong with his heart.(Doctors will do an echo and EKG next week.) He is very fair-skinned, and I wonder if anyone has heard of this happening because of sensitive skin reacting to cold. How likely is this to be nothing to worry about? Thanks

[Kevin Kennedy, Ph.D.]

Dear Camille,

Generally, this is a benign condition and really is nothing to worry about. You are undertaking the sensible diagnostic routines to rule out any underlying medical problem, and don't be too surprised if everything checks out OK.