secondary to infections (either chest or UTI) is a common occurence in children and unlikely related to azithromycin
. Many children are misdiagnosed as antibiotic allergy
in such situations but it is important you keep this at the back of your mind should this occur in the future.
Levocetirzine syrup and antibiotics should be continued and levocetirizine
upto twice daily for at least one week. Occasionally you may need to continue with antihistamines for a month if the urticaria is not settling.
Hope that was useful.