Three possible reasons could be 1) The intensity of his exercise. 2) (Possibly but not for sure) Fifth disease, 3).Lupus(butterfly rash),but it's probably best to have his mom to follow up with a doctor to make sure there isnt any serious underlying illness.

At my peak of health and fitness at age 17, the school nurse called me in from gym to get my vision checked. I walked into her office, still pleasantly winded from the track and field activity I had just completed. She asked me if I wanted to sit down. Twice. I had to get a bit older before I recognized that she thought I might have a coronary. I still flush a disturbing deep red with little provocation. I have no endocrine disorders or ailments of any kind, and am now in my fifties ...

Certainly, someone should mention it to the child's doctor. But if the youngster has a fair complexion, that flush may be nothing more than healthy circulation.

Hi Grandma Jan. At 5 years of age, more than likely your grandson's flushing is simply the body's mechanism for cooling. The redness is more obvious with people that are fair-skinned. I have noticed people that seem to turn a much darker red shade and it still be a normal reaction.

Of the conditions you mentioned, both endocrine disorders, (Addison's disease and endogenous Cushing's syndrome), can cause high blood pressure over an extended period of time. The resulting high blood pressure can produce intense facial redness and flushing. However, this is not likely an issue for your 5 year old grandson. It is likely nothing to be concerned about, but should be mentioned to his pediatrician as a precautionary measure.

This person spoke to my concerns of endocrine involvement, altho' I didn't mention high blood pressure, and, no, it isn't an issue for my grandson.

The other two responses were equally reassuring; it was hard to choose "the best." His red face doesn't resemble either Fifth's Disease or the butterfly rash of lupus. I was interested in these suggestions, too.

But, as all three responses suggested--especially the 17 y/o--it's most likely a normal response to physical stress. I'll ask my daughter if she's mentioned his exercise-induced-red-face to his pediatrician. Thank you, all.
Grandma Jan

You are very welcome, Grandma Jan. I appreciate your concern for your grandson and hope you and your family have a Happy Thanksgiving. Have a great day.