The red leg dilemma: a scoping review of the challenges of diagnosing lower-limb cellulitis

Utilization of CT for Extremity Cellulitis: A Retrospective Single-Center Analysis

PURPOSE

Routine imaging of soft tissue infection is not recommended and represents a potential area of CT overuse. The utility of CT in patients with superficial soft tissue infection of the extremities is unknown. The purpose of this study is to evaluate the utilization and clinical impact of CT ordered in the setting of extremity cellulitis.

METHODS

We retrospectively analyzed patients with extremity cellulitis examined with CT between 2012 and 2021 at a single center. We collected patient history, diagnostic imaging characteristics, and subsequent surgery decision. We hypothesized that yield of CT for deep infection was significantly lower than 10% and that yield was decreasing over time. These hypotheses were evaluated with Rao-Scott χ2 tests and repeated measures logistic regression.

RESULTS

There were 496 eligible encounters among 463 patients. Yield of positive CT among lower extremity patients was 5.5% (95% confidence interval 3.33-7.75), significantly less than our hypothesis of 10% (P = .003). In 71.8% of encounters, patients underwent diagnostic imaging studies in addition to CT. Utilization rose from 0.08% per hospital visit in 2012 to 2013 to 0.14% in 2020 to 2021, with differences in yield between time periods not reaching statistical significance (P = .059). Among 496 encounters, 62 received surgery (12.1%), with 21 of these cases preceded by a positive CT for deep infection.

CONCLUSIONS

Our 10-year single-center analysis of CT use for extremity cellulitis demonstrated a low yield of positive CT findings for deep infection and limited impact of CT on surgical management. A high incidence of patients undergoing multiple radiologic examinations suggests uncertainty in selecting appropriate imaging modalities in this clinical scenario.

SUMMARY

This single-center retrospective analysis found that CT examination of patients with clinically diagnosed cellulitis of the extremities has significantly low yield for deep infection in the lower extremities.

Red Leg Dilemma: Development and Validation of Clinical Decision Tools for Non-Necrotizing Bacterial Dermohypodermitis, Necrotizing Fasciitis, and Eczematous Dermatitis

BACKGROUND

Diagnosing red legs on first presentation is challenging. There exists a lack of robustly developed and validated diagnostic red leg tools in clinical practice. Physicians fear missing cases of infectious red legs and treat many patients unnecessarily with antibiotics.

OBJECTIVE

Develop and validate easy-to-use diagnostic tools applicable at bedside of patients to orient diagnosis of the commonest and most serious causes of infectious red legs (non-necrotizing bacterial dermohypodermitis (NNBDH), and necrotizing fasciitis (NF)) versus the commonest inflammatory cause (eczema).

METHODS

We collected data of patients presenting to our dermatology department from January first 2012 until May 17th 2017 with a diagnosis of red leg. Three models were developed using fast frugal trees. Validation was performed in a second cohort of patients.

RESULTS

A total of 187 patients (mean age 56, SD = 21 years, 48.1% women) were included in the development phase and 62 patients (mean age 64, SD = 19, 52% women) in the validation phase. In the validation data set, sensitivity and specificity were respectively 67% and 91% for NNBDH, 83% and 66%, for NF and 88% and 93%, for eczema.

CONCLUSION

Presentations of suspected lower-limb infections are commonly misdiagnosed, resulting in avoidable antibiotic prescription and hospitalization. We developed an easy-to-use clinical diagnostic tool applicable at the bedside of patients to help orient physicians in certain situations and avoid unnecessary initiation of antibiotics. Future work should focus on validating this tool in primary care to minimize misdiagnosis of red legs and overprescription of antibiotics.

Using Thermal Imaging to Track Cellulitis

Background

Cellulitis is a common soft tissue infection and a major cause of morbidity. The diagnosis is based almost exclusively on clinical history and physical exam. To improve the diagnosis of cellulitis, we used a thermal camera to track how skin temperature of the affected area changed during a hospital stay for patients with cellulitis.

Methods

We recruited 120 patients admitted with a diagnosis of cellulitis. Daily thermal images of the affected limb were taken. Temperature intensity and area were analyzed from the images. Highest daily body temperature and antibiotics administered were also collected.We estimated a longitudinal linear mixed-effects model with a random intercept for the affected body area. All observations on a given day were included, and we used an integer time indicator indexed to the initial day (ie, t = 1 for the first day the patient was observed, etc.). We then analyzed the effect of this time trend on both severity (ie, normalized temperature) and scale (ie, area of skin with elevated temperature).

Results

We analyzed thermal images from the 41 patients with a confirmed case of cellulitis who had at least 3 days of photos. For each day that the patient was observed, the severity decreased by 1.63 (95% CI, -13.45 to 10.32) units on average, and the scale decreased by 0.63 (95% CI, -1.08 to -0.17) points on average. Also, patients' body temperatures decreased by 0.28°F each day (95% CI, -0.40 to -0.17).

Conclusions

Thermal imaging could be used to help diagnose cellulitis and track clinical progress.

Bullous skin signs and laboratory surgical indicators can quickly and effectively differentiate necrotizing fasciitis from cellulitis

OBJECTIVES

The purpose of this prospective study was to investigate the different microorganisms associated with mortality, to evaluate the bullous skin sign, and to identify the positive predictive factors for differentiating necrotizing fasciitis (NF) from cellulitis on initial onset at the emergency department.

METHODS

This prospective study was conducted in 145 consecutive patients with NF and 159 patients with cellulitis. Age, sex, comorbidities, infection site, microbiological results, condition of skin lesions, laboratory findings, vital signs, and clinical outcomes were compared between the two groups at the time of admission to the emergency room.

RESULTS

A total of 15 patients in the NF group and two patients in the cellulitis group died, resulting in a mortality rate of 10.3% and 1.3%, respectively. The NF group had a significantly higher incidence of white blood cell counts, band form neutrophil, and C-reactive protein than the patients in the cellulitis group. Hemorrhagic bullae presentation appeared to have significantly associated with NF and death.

CONCLUSION

The following diagnostic indicators can be effectively used to differentiate NF from cellulitis at the initial onset: presence of hemorrhagic bullae, white blood cell counts >11,000 cells/mm³, band forms >0%, C-reactive protein >100 mg/l, and systolic blood pressure ≤90 mm Hg at the time of consultation.

Prevalence of misdiagnosis of cellulitis: A systematic review and meta-analysis

BACKGROUND

There is no gold standard test to accurately identify patients with cellulitis and therefore misdiagnosis is common. Using the clinical impression of a dermatology or an infectious disease specialist as a reference standard, we sought to determine the prevalence of misdiagnosis of cellulitis among nonspecialist physicians.

METHODS

A systemic search was performed using MEDLINE, Cochrane Library, and EMBASE databases for studies reporting diagnostic accuracy of cellulitis. Inclusion criteria required dermatology or infectious disease consultation for all patients diagnosed with cellulitis by generalist physicians. We used random effects modeling to estimate the prevalence of misdiagnosis using consultant diagnosis as a reference standard.

RESULTS

Eight studies contributed to the analysis. For the seven studies involving inpatients, the results were sufficiently homogeneous to justify pooling data. Of 858 inpatients initially diagnosed with cellulitis, 335 (39%, 95% confidence interval: 31-47) received an alternative diagnosis from the specialist. Heterogeneity was large (I²  = 74%) and the greatest contributor to between-study variance was the year of publication. Alternative diagnoses were mostly noninfectious (68%, 221/327), with stasis dermatitis (18%, 60/327) being the most common. An abscess was the most common alternative infectious diagnosis (10%, 32/327).

DISCUSSION

Cellulitis is commonly misdiagnosed among inpatients, leading to unnecessary hospital admissions and antibiotic overuse. Most alternative diagnoses are noninfectious. Continuing medical education among general practitioners and urgent care providers will likely reduce cellulitis misdiagnoses.

Confusion With Presentations of Calcium Pyrophosphate Dihydrate Disease: A Report of Two Cases Mistaken for Cellulitis

Both pseudogout and cellulitis are diseases that may mimic one another in clinical practice. We discuss two cases of acute calcium pyrophosphate dihydrate (CPPD) arthritis mistaken for cellulitis in the emergency department. Both patients experienced significant improvement after management was changed to treat CPPD. These cases highlight how it is essential for physicians to consider CPPD as a differential diagnosis for a patient that is presenting with signs of inflammation in any joint.

Red legs: how to differentiate between cellulitis, venous eczema and lipodermatosclerosis

Community nurses often encounter people with red legs. There are a number of reasons why an individual may develop red legs. The most common causes of red legs are cellulitis, venous eczema and lipodermatosclerosis. All have different causes and require different treatments. This article aims to enable readers to differentiate between these conditions which can appear similar, and to offer effective evidence-based care.

S1 guideline: Differential diagnosis of acute and chronic redness of the lower legs

Acute or chronic redness of the lower leg is a frequent reason for visits to clinics and practices. The differential diagnosis is often challenging. The aim of this guideline is to define criteria and procedures for the differential diagnosis of acute or chronic, unilateral or bilateral redness of the lower leg. Finding the correct diagnosis is essential for selecting an appropriate treatment and can help to reduce the inappropriate use of antibiotics. The guideline committee identified the most relevant differential diagnoses: 1. erysipelas, 2. stasis dermatitis, 3. hyperergic ictus reaction, 4. superficial and deep vein thrombosis, 5. gout, 6. chronic allergic contact dermatitis, and 7. acute toxic or allergic contact dermatitis. Algorithms/diagnostic pathways, each of which can be broken down into anamnesis, clinical examination, and diagnostics, have been developed for these seven diagnoses. In addition, the guideline group identified over 40 other relevant diagnoses and summarized their characteristics in a table to facilitate further differential diagnoses.

Bilateral Lower Limbs Cellulitis: A Narrative Review of an Overlooked Clinical Dilemma

Bilateral lower limbs cellulitis is a rare clinical condition, which has been overlooked for a long time. In daily clinical practice, bilateral cellulitis is a sporadically encountered condition; however, it remains a clinical challenge. There is a broad differential diagnosis for this clinical entity, and there is a lack of accepted international diagnostic criteria. Unnecessary antibiotic prescription is common, which has led to an emerging problem. In this review, we summarize case reports of bilateral lower limbs cellulitis and common pathogens that have been documented.

Diagnosis and Management of Cellulitis and Abscess in the Emergency Department Setting: An Evidence-Based Review

BACKGROUND

Cellulitis and abscess are a common reason for presentation to the emergency department, although there are several nuances to the care of these patients.

OBJECTIVE

The purpose of this narrative review article was to provide a summary of the background, pathophysiology, diagnosis, and management of cellulitis and abscesses with a focus on emergency clinicians.

DISCUSSION

The most common bacteria causing cellulitis are Staphylococcus aureus, Streptococcus pyogenes, and other β-hemolytic streptococci, and methicillin-resistant S. aureus is most common in abscesses. The history and physical examination are helpful in differentiating cellulitis and abscess in many cases, and point-of-care ultrasound can be a useful tool in unclear cases. Treatment for cellulitis typically involves a penicillin or cephalosporin, and treatment of abscesses is incision and drainage. Loop drainage is preferred over the traditional incision and drainage technique, and adjunctive antibiotics can be considered. Most patients can be managed as outpatient.

CONCLUSIONS

It is essential for emergency physicians to be aware of the current evidence regarding the diagnosis and management of patients with cellulitis and abscess.

The Red Legs RATED tool to improve diagnosis of lower limb cellulitis in the emergency department

BACKGROUND

Lower limb cellulitis poses a significant burden for the Irish healthcare system. Accurate diagnosis is difficult, with a lack of validated evidence-based tools and treatment guidelines, and difficulties distinguishing cellulitis from its imitators. It has been suggested that around 30% of suspected lower limb cellulitis is misdiagnosed. An audit of 132 patients between May 2017 and May 2018 identified a pattern of misdiagnosis in approximately 34% of this cohort.

OBJECTIVE

The aim of this pilot project was to develop a streamlined service for those presenting to the emergency department with red legs/suspected cellulitis, through introduction of the 'Red Leg RATED' tool for clinicians.

METHOD

The tool was developed and introduced to emergency department clinicians. Individuals (n=24) presenting with suspected cellulitis over 4 weeks in 2018 were invited to participate in data gathering. Finally, clinician questionnaire feedback regarding the tool was evaluated.

RESULTS

Fourteen participants consented, 6 female and 8 male with mean age of 65 years. The tool identified 50% (n=7) as having cellulitis, of those 57% (n=4) required admission, 43% (n=3) were discharged. The remainder who did not have cellulitis (n=7) were discharged. Before introduction of the tool, all would typically have been admitted to hospital for further assessment and management of suspected lower limb cellulitis. Overall, 72% (n=10) of patients who initially presented with suspected cellulitis were discharged, suggesting positive impact of the tool. Clinician feedback suggested all were satisfied with the tool and contents.

CONCLUSION

The Red Leg RATED tool is user friendly and impacts positively on diagnosis treatment and discharge. Further evaluation is warranted.

Distinguishing Cellulitis from Its Noninfectious Mimics: Approach to the Red Leg

Cellulitis is a common clinical diagnosis in the outpatient and inpatient setting; studies have demonstrated a surprisingly high misdiagnosis rate: nearly one-third of cases are other conditions (ie, pseudocellulitis). This high rate of misdiagnosis is thought to contribute to nearly $515 million in avoidable health care spending in the United States each year; leading to the delayed or missed diagnosis of pseudocellulitis and to delays in appropriate treatment. There is a broad differential diagnosis for pseudocellulitis, which includes inflammatory and noninflammatory conditions of the skin. Accurate diagnosis of the specific condition causing pseudocellulitis is crucial to management, which varies greatly.

An interview study to determine the experiences of cellulitis diagnosis amongst health care professionals in the UK

OBJECTIVES

To explore healthcare professionals (HCPs) experiences and challenges in diagnosing suspected lower limb cellulitis.

SETTING

UK nationwide.

PARTICIPANTS

20 qualified HCPs, who had a minimum of 2 years clinical experience as an HCP in the national health service and had managed a clinical case of suspected cellulitis of the lower limb in the UK. HCPs were recruited from departments of dermatology (including a specialist cellulitis clinic), general practice, tissue viability, lymphoedema services, general surgery, emergency care and acute medicine. Purposive sampling was employed to ensure that participants included consultant doctors, trainee doctors and nurses across the specialties listed above. Participants were recruited through national networks, HCPs who contributed to the cellulitis priority setting partnership, UK Dermatology Clinical Trials Network, snowball sampling where participants helped recruit other participants and personal networks of the authors.

PRIMARY AND SECONDARY OUTCOMES

Primary outcome was to describe the key clinical features which inform the diagnosis of lower limb cellulitis. Secondary outcome was to explore the difficulties in making a diagnosis of lower limb cellulitis.

RESULTS

The presentation of lower limb cellulitis changes as the episode runs its course. Therefore, different specialties see clinical features at varying stages of cellulitis. Clinical experience is essential to being confident in making a diagnosis, but even among experienced HCPs, there were differences in the clinical rationale of diagnosis. A group of core clinical features were suggested, many of which overlapped with alternative diagnoses. This emphasises how the diagnosis is challenging, with objective aids and a greater understanding of the mimics of cellulitis required.

CONCLUSION

Cellulitis is a complex diagnosis and has a variable clinical presentation at different stages. Although cellulitis is a common diagnosis to make, HCPs need to be mindful of alternative diagnoses.

Production of the electronic British Lymphology Society Red Legs Pathway

Antibiotic misuse is a rampant problem the world over and it in turn leads to other issues, the main one being the rise of antibiotic-resistant microorganisms. Often, bilateral red legs are mistaken for acute cellulitis, an infection of the skin, and are inappropriately treated with antibiotics. The British Lymphology Society's Red Legs Pathway aims to support differential diagnosis in patients with bilateral red legs to enable prompt and effective management and improve patient experience. The pathway also aims to reduce inappropriate use of antibiotics and potential negative consequences. This article provides a brief outline of the pathway and its development.

Confidence of recurrent cellulitis self-diagnosis among people with lymphoedema: a qualitative interview study

BACKGROUND

Cellulitis can sometimes be challenging for healthcare professionals to diagnose, with no validated diagnostic criteria available. Supporting healthcare professionals to make a more accurate diagnosis of cellulitis in different groups, such as those with lymphoedema, is a cellulitis research priority. However, to the authors knowledge, no previous studies have looked at the involvement of non-healthcare professionals in the diagnostic process.

AIM

To explore the experience of people with lymphoedema and recurrent cellulitis in the diagnosis of lower-limb cellulitis.

DESIGN AND SETTING

Single, semi-structured, qualitative interviews carried out between 29 October and 19 December 2018.

METHOD

Adults with a suspected episode of cellulitis who had been diagnosed in the last 12 months or had a history of recurrent cellulitis were interviewed.

RESULTS

Three key themes emerged: the recurrent nature of cellulitis symptoms, participants' experience of getting a cellulitis diagnosis, and participants' suggestions of how cellulitis diagnosis might be improved. Generally, people with lymphoedema experienced similar clinical features during each of their own recurrent cellulitis episodes and were confident that they could make a self-diagnosis of cellulitis. This is also reflected in the participants' perceived trust from the healthcare professional in being able to make a self-diagnosis. A diagnostic checklist and educational resources were suggested as methods to improve diagnosis.

CONCLUSION

Selected people with lymphoedema who have recurrent cellulitis are confident in self-diagnosing their own recurrent cellulitis episodes. There may be a role for greater involvement of people with lymphoedema in their cellulitis diagnosis.