Final answer:
The 12-year-old female with daily fevers, rash, and swollen knees could be diagnosed with fifth disease. Good prognostic factors include mild symptoms and resolution without treatment, while bad prognostic factors can include joint pain and severe anemia. Symptom relief is usually the first-line treatment, and serological testing can confirm the diagnosis.
Step-by-step explanation:
The diagnosis for the 12-year-old female with a 2-week history of daily fevers, salmon-colored rash on her trunk, thighs, and shoulders, and swollen left and right knees could be fifth disease, also known as erythema infectiosum. Fifth disease is caused by parvovirus B19 and is more common in children than adults. Some good prognostic factors for fifth disease include mild symptoms and resolution without medical treatment, especially in children. Some bad prognostic factors include joint pain and swelling lasting several weeks or months in adults and severe anemia in immunocompromised individuals. The first-line treatment for fifth disease is usually focused on symptom relief, as the disease resolves on its own without medical treatment in children. Serological testing can confirm the diagnosis.