My daughter has been taking Singulair for about 2 months. She now has hives or a rash on her face, arms and legs (and some in diaper area). She is on an antibiotic for a chronic sinus infection as well. The doctor says it is impetigo but her "welts" are not oozing. I am putting Bactroban on it and will see if it help. My worry is that it is really hives from the Singulair. Wouldn't her antibiotic help the impetigo?