My 4 yr old seems to have frequent runny nose with yellow colored mucus. Is it true that yellow means infection? I call the CF clinic when she has this, usualy every 6 weeks or so, and they put her on antibiotics. Could this mean she has sinus problems? Allergies??? Im not sure what to make of it. My 6 yr old also has CF and never has this reacurrent respitory infection. Thanks! Jen