My son has influenza a. he is 15 months. he has a rash on his face now, is that common?

Flu and rash: Rashes are not uncommon accompanying influenza, particularly in children. However, many childhood disease also present with rashes, and one called "fifth disease" or parvovirusb19 has a facial rash that is often referred to as a "slapped cheek" rash. Perhaps your son does not have the flu, but fifth disease? Symptoms could easily be mistaken one for the other.

Viral rash: A viral illness may be associated with a rash, but if it is itchy, consider an allergic reaction. Apply a baby lotion with no fragrance to moisturize the skin and watch for signs of local infection such as drainage and redness.