Hello dear, Thank you for your question. In my opinion, the timeline of your complaints suggests of @Scarlet fever. This is a reaction of the body to an infection from @Streptococcus. This condition explains why all symptoms, except the rash, are fading. Even though the rapid strep test result came negative, that doesn t mean that the Streptococcus infection wasn t present. That s why I always refer my patients for a throat swab culture. Since your child has been getting better from Erythromycin, which covers Streptococcus, it safe to say that this infection was most likely from Streptococcus. Under antibiotic treatment, this situation resolves within a few days. The rash is the last symptom to leave, a process which can take up to several weeks. Meanwhile your child can go to school since the disease is no longer contagious. I hope this was helpful. Kind regards, Dr. Alma