How to confirm or rule out rheumatic fever?

Hello doctor,

I am currently facing a diagnostic challenge. I woke up one day with a full-body infective impetigo. My doctor diagnosed it visually as a staph infection and prescribed Augmentin. However, after a week with no improvement, I was switched to Cephalexin. Despite another week passing, a skin swab yielded no culture.

The doctor suggested stopping antibiotics to obtain a culture. Shortly after, I developed strep throat, which lasted for several days. Another skin culture was performed, and I was put on Doxycycline for the infective impetigo.

Although the skin culture came back negative, I was instructed to continue Doxycycline and also started Dicloxacillin.

Around the beginning of last month, I began experiencing an increased heart rate, chest pain, weight loss (about 22 lbs), tiredness, subcutaneous nodules (five), headaches, shifting arthritic pain in knees and ankles, leg and arm swelling, and a mildly sore throat. ASOT/Anti-DNase B testing showed ASOT: 60 and Anti-DNase B: 196, both below the limits for strep. However, considering the extended antibiotic treatment before testing, can antibiotics keep titer limits low and mask bacteria from being cultured?

My doctors say no, but I have read that it is possible, especially in cases of rheumatic fever with two major Jones criteria evident. I have been off antibiotics for five days now and will continue with titer testing weekly and echocardiograms monthly to find an answer. All autoimmune and rheumatic factors, as well as septic arthritis, have been ruled out via blood tests. It seems rheumatic fever is highly probable.

My medical history includes seven weeks of whole-body infective pyoderma/impetigo, strep throat or tonsillitis five weeks ago, chest pain, shortness of breath, tiredness, weight loss (about 22 lbs), knee pain, leg swelling, arm swelling, nodules, and arthritic movements, etc., two weeks ago.

Kindly help.

Thank you.

Hello doctor

Thank you for your reply.

Here are the results of the investigations:

CRP:

1. 34 mg/dL - (two months ago).

2. 22 mg/dL - (two months ago).

3. 8.5 mg/dL - (one month ago).

4. 5 mg/dL - (one month ago).

ESR:

1. 20 mm/hr - (two months ago).

2. 5 mm/hr - (one month ago).

Unfortunately, I am unable to access my previous CBC results at the moment. However, during that time, I was on dual antibiotics and Prednisone. I have completed my course of antibiotics (Dicloxacillin for 10 days and Doxycycline for five full days), but my symptoms have worsened. I plan to retest weekly accordingly. Could ASOT/ADNB levels rise now that I am off all antibiotics or Prednisone?

Additionally, what other tests can I undergo to confirm a previous or current strep infection besides ASOT/ADNB? Is there a test for M proteins or similar indicators? Perhaps a subcutaneous nodule biopsy? If I can not scientifically prove I had strep throat or skin infection despite meeting two major Jones criteria and experiencing other symptoms, my doctors would not prescribe me a penicillin G injection or diagnose me with rheumatic fever. However, I strongly believe I have it based on the criteria and after ruling out other diseases.

I feel truly lost in this situation and would appreciate your guidance. Kindly help.

Thank you.

Hello doctor,

Thank you for your reply.

My concern is that Cephalexin was only used for six days before the onset of strep throat. Strep throat occurred after the administration of Cephalexin. CRP levels are known to decrease, particularly after treatment with Doxycycline alone, or in combination with Prednisone. Doxycycline was administered 10 to 12 days after the strep throat infection, followed by the onset of sequelae symptoms 14 days after the strep throat infection.

My doctors adhere strictly to administering Penicillin G injections based on elevated ASOT/ADN-B levels, regardless of the presence of Jones criteria. However, it is worth noting that some sequelae can also cause a decrease in ASOT/ADN-B levels.

Are there alternative tests, such as anti-hyaluronidase or M-protein detection, to confirm strep infection or rheumatic fever? Could a subcutaneous nodule biopsy be considered as well?

Kindly help.

Thank you.