Atypical Erysipelas: Bullae, Necrosis, Diagnosis & Treatment
Atypical Erysipelas: Recognizing a Challenging Skin Infection
Table of Contents
Published September 1, 2025
Understanding Erysipelas and its Unusual Presentation
Erysipelas is a bacterial skin infection, most commonly caused by Streptococcus pyogenes, typically presenting with a distinct, raised, and sharply demarcated border. However, a recent case highlights a more complex and delayed diagnostic scenario involving atypical features. This case, observed in a 73-year-old male, demonstrates that erysipelas can sometimes manifest with serohematic bullae (fluid-filled blisters containing both serum and blood) and areas of necrosis (tissue death), significantly complicating initial assessment.
The Case: Delayed Diagnosis and Complications
The patient initially presented with symptoms on his lower limbs. The infection progressed despite initial antibiotic treatment with amoxicillin and clavulanate.The advancement of large, serohematic bullae and subsequent necrosis led to a diagnostic delay, initially misconstrued as a pressure ulcer or other dermatological condition. The patient’s medical history included chronic venous insufficiency and a previous below-knee amputation, factors that initially obscured the true nature of the infection.
Diagnostic Challenges and Key Findings
The atypical presentation-specifically the bullae and necrosis-distinguished this case from typical erysipelas.Blood cultures were negative, ruling out bacteremia. However,a skin biopsy ultimately confirmed the diagnosis of erysipelas. Imaging, including a lower limb angiography, was performed to exclude arterial disease, which could contribute to necrosis, but revealed no significant abnormalities. The patient also exhibited elevated C-reactive protein (CRP) levels, indicating inflammation.
Treatment and Management
Following the confirmed diagnosis, the patient’s treatment was adjusted to intravenous antibiotics, specifically cefazolin.Debridement of the necrotic tissue was also performed. This change in therapeutic approach led to gradual improvement,with the bullae resolving and signs of inflammation decreasing. The patient required a prolonged hospital stay of 21 days due to the severity and delayed diagnosis of the infection.
Implications for Healthcare Professionals
This case underscores the importance of considering atypical presentations of erysipelas,particularly in patients with underlying vascular conditions or compromised immune systems. A high index of suspicion, coupled with prompt skin biopsy when clinical presentation is unclear, is crucial for accurate diagnosis and timely intervention. Delayed diagnosis can led to increased morbidity, prolonged hospitalization, and potential complications like sepsis. Recognizing the potential for serohematic bullae and necrosis as features of erysipelas can significantly improve patient outcomes.