Cellulitis is a common medical condition that presents as an acute inflammation of the skin and subcutaneous tissue, usually as a result of bacterial infection, and cellulitis of the lower limb is often referred to as a ‘red leg’. It can be a difficult diagnosis to make because it has many differential diagnoses that result in similar presentations of red, warm, painful swollen limbs. There are no definitive diagnostic tests to confirm cellulitis; diagnosis is made based on clinical evaluation with evaluation of inflammatory marker results (Quirke et al, 2017; Santer et al, 2018; Sullivan and de Barra, 2018; Patel et al, 2019a; Patel et al, 2019b; Teasdale et al, 2019). Cochrane reviews (Kilburn et al, 2010; Dalal et al, 2017) have indicated a dearth of evidence-based guidelines with few reported clinical trials addressing the difficulties encountered by clinicians in making an accurate diagnosis, preventing recurrence and the impact on patients who suffer from red leg syndromes.
It is estimated that 30% of patients presenting with red legs are often inappropriately admitted to hospital (Levell et al, 2011; Wingfield, 2012; Yarbrough et al, 2015; Jain et al, 2017; Weng et al, 2017; Patel et al, 2019b; Edwards et al, 2020). This results in inappropriate use of antibiotics and delays in diagnosis, which are costly for both the patient and service provider (Raff and Kroshinsky, 2016; Weng et al, 2017).. Often the risk factors for cellulitis such as chronic oedema or tinea pedis/athlete's foot are not recognised or treated, exposing the patient to recurrent episodes of cellulitis. Inappropriate or untreated cellulitis can lead to severe complications ranging from sepsis to tissue necrosis and even death (Stevens et al, 2014).
Although international guidelines pertaining to cellulitis exist (Clinical Resource Efficiency Support Team (CREST), 2005; Stevens et al, 2014; National Institute for Health and Care Excellence (NICE), 2019) there are no national guidelines in the Irish Healthcare service. Thus, clinicians are faced with a dearth of updated clinical evidence and diagnostic strategies or tools to guide clinical decisions to accurately identify, admit and treat patients presenting with cellulitis. This poses a challenge in differentiating cellulitis from other conditions (Wingfield, 2012; Elwell, 2015; Patel et al, 2019b). The potential misdiagnosis is due to presenting symptoms such as red, warm, tender or painful skin, which can also be symptoms of other inflammatory skin conditions such as stasis dermatitis or lipodermatosclerosis, or of acute venous issues such as deep venous thrombosis, oedema, irritant contact dermatitis or vasculitis (Hirschmann and Raugi, 2012a; 2012b).
This presents problems in clinical practice. For example, patients with chronic lower limb oedema are often admitted with a diagnosis of bilateral cellulitis and prescribed antibiotics. The redness and swelling frequently resolves with bed rest, resulting in early discharge with the assumption that the cellulitis has responded to the antibiotics. However, this cohort of patients are frequently readmitted with recurrence of symptoms, which is then assumed to be failure to respond to treatment and they are recommenced on stronger antibiotics (Quirke et al, 2017). Often these patients had improved during the initial admission due to bed rest and elevation as they have underlying conditions such as chronic venous insufficiency or congestive heart failure, which cause lower limb swelling leading to redness and pain. Once they go home this swelling often reoccurs as the patients either are not resting or do not elevate their limbs. These underlying chronic conditions require appropriate management in order to prevent inappropriate hospital admission. Failure to recognise, address and educate both clinicians and patients about these chronic complex conditions will result in future multiple, potentially avoidable admissions (Quirke et al, 2017). Following a systematic review and meta-analysis considering risk factors for non-purulent cellulitis, Quirke et al (2017) recommended that clinicians should address modifiable risk factors, such as wounds, ulcers, lower limb oedema and toe-web intertrigo.
Quirke et al (2017) examined the challenges and facilitators in diagnosing lower limb cellulitis, reporting a lack of good-quality tools or criteria for diagnosing lower limb cellulitis. They also recommended that future research should examine from a qualitative perspective the challenges faced by both clinicians and patients when presented with diagnostic dilemmas pertaining to cellulitis and its mimickers. As no exact diagnostic test for cellulitis exist, clinicians rely on their clinical experience and interpretation of results such as inflammatory blood markers. This, coupled with the absence of clear national guidelines, can potentially lead to misdiagnosis or over diagnosis of severity of infection (Hirschmann and Raugi, 2012b) resulting in:
- Inappropriate antibiotic use in an era of rising antibiotic resistance
- Prolonged length of hospital stay
- Recurrence due to mismanagement
- Failure to manage the true diagnosis
- Poor patient outcomes
- Misuse of finite resources.
Strategies are needed to reduce unwarranted variation in care with a focus on resourcing care that benefits the patient in line with Ireland's Health Service Executive (HSE) ethos of right care by the right person, in the right place at the right time. An Irish study audited antibiotic use in patients admitted with skin and soft tissue infections in an Irish hospital setting (Kiely et al, 2020), and the authors suggested that adherence to international guidelines would significantly reduce unnecessary admission, avoid over consumption of unnecessary antibiotics and improve antimicrobial stewardship. UK research has reported similar findings (Elwell, 2015; Weng et al, 2017; Patel et al, 2019b). A UK alliance was established including both patients and practitioners to establish research priorities pertaining to cellulitis with particular focus on the qualitative aspects associated with clinicians and diagnosing appropriately and patient experience (Thomas et al, 2017).
Improving management of patients presenting with ‘red leg’
The first author is employed as a Registered Advanced Nurse Practitioner (RANP) in tissue viability and dermatology in an acute hospital setting in Ireland. This article describes a recent RANP-led pilot project that involved the introduction of a ‘Red Leg RATED’ tool streamlining the process for patients presenting to an emergency department with suspected lower limb cellulitis, by showing information on differential diagnosis or imitators of cellulitis.
Data extracted from the hospital inpatient enquiry system system reported 132 inpatient admissions with a diagnosis of lower limb cellulitis between May 2017 and May 2018. Associated length of stay exceeded 1200 days with a mean length of stay reported as 9.16 days at a cost of €1 038 531, excluding associated costs of consumables or antibiotics. Per patient admitted it costs approximately €10 000 per stay. A retrospective chart review suggested that approximately 34% of those were misdiagnosed with cellulitis and potentially could have been discharged with outpatient management and RANP follow-up care. Recognising these data, the potential misdiagnosis of cellulitis and issues in clinical practice, the RANP in collaboration with an expert group proposed the development of a tool to assist clinicians in the diagnosis and subsequent management of cellulitis, or in forming a differential diagnosis. Further, a pilot project would seek to evaluate the use of a tool in identifying cellulitis versus a differential diagnosis and appropriately managing cellulitis in a cohort of patients presenting to the emergency department. Additionally, clinician feedback of the tool in clinical practice would be evaluated.
The overarching aim of the proposed pilot project was to develop a streamlined service facilitated through use of the tool that fulfils the ‘right person, right place, right time, and right team’ ethos underpinning the Irish healthcare service in diagnosing and appropriately treating suspected cellulitis in an emergency department.
Methods
Ethical approval
Ethical approval was granted from the hospital ethics committee to undertake a 4-week pilot study in August 2018. All identified potential participants (n=24) were informed of the study through a gatekeeper and 14 (58%) consented.
Expert group
An expert group was formed in June 2018 (Box 1). The premise of the expert group was to develop a tool to improve diagnostic accuracy of lower limb cellulitis, identify possible differential diagnosis and put in place a plan of care to manage the conditions diagnosed. An exhaustive list of potential differential diagnoses was considered inappropriate; the top differential diagnoses as identified in literature as imitators of cellulitis were chosen to be included in the tool.
Box 1.Key stakeholders in the Red Leg expert group
- Advanced nurse practitioner tissue viability/dermatology x 1
- Dermatology consultant x 2
- Emergency medicine consultant x 2
- Vascular consultant x 1
- General surgeon x 1
- Microbiologist x 1
- Antimicrobial stewardship pharmacist x 1
- Research support provided by a post-doctoral researcher and an academic from a partnering university
Collaboratively, a management care pathway was included for each potential differential diagnosis with provision for RANP outpatient follow-up for patients whom were discharged home to ensure re-evaluation of their condition. Guidance was also included in the tool pertaining to criteria for admission, suitability for outpatient services and alerts for serious conditions such as necrotising fasciitis, with links to local prescribing guidelines for skin and soft tissue infections (Figure 1).
Figure 1. Sample of differential diagnosis of suspected cellulitis
Red Legs RATED tool development
The development of the Red Legs RATED tool occurred using a Plan Do Study Act (PDSA) cycle, incorporating expert feedback, staff education, a pilot phase and evaluation of ease of use of the tool with user feedback. The Red Leg RATED tool included descriptive criteria and images for the identification of cellulitis with recommendations for management and follow-up.
Education
Prior to use of the Red Leg RATED tool education sessions were planned with all emergency department staff over a 4-week period beginning in July 2018. Clinicians, specifically non-consultant hospital doctors, consultants, RANPs and nursing staff were provided with interactive face-to-face education sessions with support from the RANP in tissue viability and the emergency department consultants. A folder was made available for all emergency department staff with educational support in use of the tool.
Retrospective chart review
A medical chart review of those who presented with red legs and suspected cellulitis over the 4 weeks was undertaken to ascertain diagnosis, management and follow-on care.
Post-pilot questionnaire
A brief questionnaire assessed user-friendliness of the tool as an aid to diagnosis following a 4-week pilot use of the newly developed and implemented Red Leg RATED tool.
Results
Fourteen (58%) of those patients presenting with red legs agreed for their data to be included. Of those, 43% (n=6) were female and 57% (n=8) were male with an overall mean age of 65 years. The Red Leg RATED tool identified 50% (n=7) true diagnosis of cellulitis, of those 57% (n=4) required hospital admission, 43% (n=3) were discharged. This discharge cohort is typically admitted to hospital for further assessment and management of suspected lower limb cellulitis. The remaining 50% (n=7) were found not to have cellulitis and discharged to expert RANP follow-up. The referral was warranted in all cases. Overall, 72% (n=10) of patients (consenting to inclusion) who presented with suspected cellulitis and would typically have been admitted to hospital were discharged. Of the completed clinician questionnaire (n=13), 100% of users were satisfied with the tool and contents, found it easy to use and felt it helped them make a more accurate diagnosis of cellulitis versus a differential diagnosis. All users agreed the education prior to using the tool was appropriate and the tool useful and of clinical benefit; 92% (12/13) reported that the tool contained the right amount of information while one respondent stated that there was too much information.
Qualitative analysis suggests all (n=13)of the non-consultant hospital doctors and RANPs who used the tool reported that the education they received was clear, comprehensive and helpful. The tool was described as ‘an extremely sophisticated tool which offers a clear pathway for diagnosing patients’. It was described by one clinician as ‘a fool-proof guide to managing (red leg) presentations’. Its value in avoiding unnecessary admissions was also noted. Box 2 reflects some of the feedback comments.
Box 2.Clinician feedback comments
- Photos of relevant differentials were great and taught me a lot I didn't know about Red Leg
- Education prior to using the tool was very comprehensive and helpful; much appreciated
- Really good training initially. Maybe a follow-up would be helpful
- Very helpful with really clear advice/criteria for admission
- Good to have guideline on who to admit and who not requiring admission
- Photos of relevant differentials were great and taught me a lot I didn't know about Red Leg
- Good guidance with clear pictures. Tick box criteria for cellulitis very helpful feels like, coupled with my experience I now have a fool-proof guide to managing the presentation, thank you!
Between May 2017 and May 2018, 132 patients were admitted to hospital with suspected cellulitis with 34% possible misdiagnosis. After the pilot project, which demonstrated the benefits of the tool, it became widely used within the emergency department setting—research is underway into the impact of this. A retrospective chart review and early data analysis suggests that within a 1-year timeframe, September 2018 to September 2019, the admission rate for cellulitis has decreased considerably. In that 1 year the tool was used with 177 patients who presented with red leg-suspected cellulitis, only 37% (n=66) patients were admitted to hospital, all were appropriately admitted. Of those discharged, only 29% (n=51) required referral to the RANP outpatient clinic for follow up regarding a differential diagnosis. The remaining 34% (n=60) were discharged to general practitioner follow-up.
Discussion
The Red Leg RATED tool seems to have benefits for both clinicians and the organisation with aid to diagnosis and potentially avoiding inpatient admissions and the associated costs with appropriate management and follow-up of care. Over a 4-week timeframe the pilot project demonstrated a potential cost saving of €100 000 with no requirement for hospital admission. The tool is user-friendly and has impacted positively on the diagnosis and treatment of cellulitis. Further research and evaluation of the tool is ongoing to determine diagnostic validity in a larger cohort and over a longer timeframe. Future research is planned with the aim of understanding the challenges patients face when presenting with red leg symptoms (red, warm, painful legs) and what effects these, and the various conditions that can cause them, have on the patient.
Limitations
The pilot study has limitations as it was undertaken in an acute adult ED of a general hospital that may not be representative of the wider population. The tool is only available in hard copy format. Data collection was also in hard copy format and was dependent on clinicians entering the data. Therefore, the full population of potential participants may not have been captured. This was particularly applicable for patients not admitted to hospital as these are not captured on the hospital inpatient enquiry system data system.
Future steps
The pilot study has provided impetus to explore the full potential impact of the tool. Subsequently, an alert system was added to the emergency department information technology system to use the tool if patients were presenting with red legs and suspected cellulitis. It is anticipated that this future research will be reported as a follow up to this pilot study.
Conclusion
Cellulitis can be difficult to diagnose but the application of the Red Legs RATED Tool in emergency care and supportive education can benefit patients, clinicians and the organisation. Improved management and prescribing practices particularly with regard to antimicrobial stewardship in an era of rising global antibiotic resistance is pivotal. Improved use of finite healthcare resources and improved patient outcomes all underpin the impetus to further explore this area of research and the reported results supports the impetus to validate the tool at a wider level.
KEY POINTS
- The introduction of a Red Leg RATED Tool in the emergency department assists clinicians in accurately diagnosing and treating lower limb cellulitis versus a differential diagnosis
- It assists clinicians in diagnosis and management through its ease of use
- It facilitates accurate diagnosis and management thereby reducing hospital admissions and associated costs
- Also facilitates follow up by an Registered Advanced Nurse Practitioner in tissue viability through a specific referral process contained in the tool
CPD reflective questions
- How would you ensure accurate diagnosis and correct management of lower limb cellulitis?
- What do you think are the potential differential diagnoses and appropriate investigations when patients present with red legs to the emergency department?
- How could you empower patients to recognise symptoms sooner in order to avoid hospital admission?