If child reacts to ibuprofen with rash should we discontinue. is it dangerous?

The big picture: One's pediatrician who knows the patient and the big picture can advise what to do. The big picture is needed here, as without the big picture, one cannot tell why there was a rash. Patients do not take ibuprofen for no reason. Therefore there was a disorder or illness that led to the ibuprofen. Many illnesses cause rashes. Perhaps other drugs were taken for the illness. Many drugs cause rashes.

Yes: Whenever someone reacts to a drug with a rash, it indicates that presence of an immune response and should be discontinued especially when there are other options such as tylenol or aleve. If he develops hives or swelling from it, he may not tolerate other NSAIDs as well. Check with your pediatrician if you have other questions.