Yes, my guess is tonsillitis too. I find that to be the main cause of bad breath in little people. Interestingly, children who are more sensitive to dairy products are often the ones who are more prone to tonsillitis. Sometimes with reoccurring tonsillitis, small crypts can form in the tonsils, and these become filled with a smelly, cheesy substance, making the breath very unpleasant.

Good idea to see your GP to find out what's going on with your little one,

All the best,
xxx