I don't know, but my first reaction was rheumatic fever. Do kids even get that anymore?I remember waaaay back in the day, I had a bad bout of strep and my mom was concerned that it might turn into rheumatic fever, because two of my cousins had it.
yes they do. and the fact that the kid went weeks without being treated due to initial misdiagnosis would make me alarmed. Sore throats should always be tested - no excuse not to, its a cheap and quick test - and it has actually stared to become a standard of care (I work for the GOV and yes - we test ALL sore throats for strep!). With the swollen joint - I would be even more concerned. Strep can have so many negative health consquences.
And, as someone else mentioned - in passing - you CAN have strep and mono at the same time - and giving amoxil to kids with mono (or viral illness), for some unknown reason, WILL cause a rash. it does not mean they are allergic to the drug. While this may not be the issue you are dealing with, this is an EXAMPLE as to why your kid really needs to be examined by a trained medical professional that will listen to your mom instincts.
You need really, really need to go to a real pediatrician who will take care of your kid and help you find out what is going on. Untreated rheumatic fever, for example, has lifelong consequences, and it is cases like this where the kid falls through the cracks (multiple times) where the kids tend to have the worst outcomes. I have taken care of multiple kids where stuff like this has happened - and they just get glossed over and glossed over until the kid has heart damage. NOT fun!
I know I said it before, but podiatrists are trained in feet, they are not physicians - its like going to an audiologist and asking him what to do in this manner. They have a doctorate in podiatry. That is it. Please go to a doctor - a DO or MD, go to a PA (physicians assistant), or a nurse practitioner (NP) - SOMEONE, anyone who has training to care for the overall health of children. Not just their feet.
Your kid has so many things going on that even a provider who is caring for your child who knows your child very well shouldn't do anything over the phone - the kid needs a good history and physical exam so they can then make a plan to go on from there (labs, meds, whatever). Until then - no one is going to know what is going on - which is very scary!
Good luck.
(Just FYI - I'm a Pediatric NP. Those are my opinions. In short - just take your baby in to get checked.)