# Uncommon Systemic Manifestation of Group A Beta-Hemolytic Streptococcus in a Middle-Aged Woman: A Case Report

## TL;DR

A middle-aged woman experienced a rare systemic reaction to a GABHS infection, showing symptoms like sore throat, rash, and joint swelling, which resolved with antibiotic treatment.

## Contribution

Highlights a rare systemic manifestation of GABHS in adults, emphasizing the need for broader diagnostic consideration.

## Key findings

- The patient showed symptoms resembling rheumatic fever despite normal WBC, CRP, and ASO levels.
- Treatment with clarithromycin and amoxicillin resolved all symptoms.
- Echocardiogram revealed mitral valve calcification and mild regurgitation.

## Abstract

Group A beta-hemolytic Streptococcus (GABHS) is a gram-positive type of bacteria, typically causing high fever and painful pharyngitis. The bacteria may sometimes trigger widespread skin rash in children, but systemic conditions other than sore throat are rare in adult patients with the infection. A 57-year-old woman visited our hospital with a sore throat, pruritic skin rash in the body trunk, painful oral ulcer, swollen lips, arthralgia, and swollen left wrist joint with pain. She had a recent similar clinical episode approximately four weeks before the hospital visit, which was alleviated with oral loxoprofen. The swelling of the left wrist had migrated from the left elbow area in the preceding four weeks. The patient had similar symptoms about 30 years ago, which were diagnosed with GABHS infection and successfully treated with oral antibiotics. Based on this past similar clinical episode, the patient was evaluated by the GABHS rapid antigen detection tests, which revealed a positive result. The blood test data showed normal white blood cell (WBC) count and C-reactive protein (CRP) level. She was free of any serum antibodies associated with autoimmune connective tissue diseases or syphilis. Deciding the diagnosis was difficult, but based on her past similar clinical episode in her 20s and systemic conditions resembling rheumatic fever, a diagnosis of GABHS-related uncommon systemic response was made. The patient was treated with clarithromycin (200 mg, twice a day) for 10 days and amoxicillin (250 mg, three times a day) for an additional seven days, and all symptoms resolved. Four weeks after the first hospital visit, the serum anti-streptolysin-O (ASO) level was normal at 135 IU/ml. An echocardiogram revealed an anterior mitral leaflet calcification with a mild level of mitral regurgitation. The present case indicated the importance of considering GABHS infection in adults with strong sore throat, widespread skin rash, arthralgia, and swollen joints with uncertain causes, even when the patient is afebrile with normal WBC count, CRP level, and ASO titer.