I have a three year old autistic grandson. He has hives and swollen joints to the point he can't walk. Took to ER they thought is was lyme disease but test came back and it's not. He was discharged but now they want him to come back. Today he was playing then all of the sudden he came down with the same thing. He is non verbal and has extreme meltdown at hospital or around any doctor. I was just wondering what he could have. He is able to walk and play after taking motrin or Tylenol. Any idea?