Original article
A predictive model for diagnosis of lower extremity cellulitis: A cross-sectional study

https://doi.org/10.1016/j.jaad.2016.12.044Get rights and content

Background

Cellulitis has many clinical mimickers (pseudocellulitis), which leads to frequent misdiagnosis.

Objective

To create a model for predicting the likelihood of lower extremity cellulitis.

Methods

A cross-sectional review was performed of all patients admitted with a diagnosis of lower extremity cellulitis through the emergency department at a large hospital between 2010 and 2012. Patients discharged with diagnosis of cellulitis were categorized as having cellulitis, while those given an alternative diagnosis were considered to have pseudocellulitis. Bivariate associations between predictor variables and final diagnosis were assessed to develop a 4-variable model.

Results

In total, 79 (30.5%) of 259 patients were misdiagnosed with lower extremity cellulitis. Of the variables associated with true cellulitis, the 4 in the final model were asymmetry (unilateral involvement), leukocytosis (white blood cell count ≥10,000/uL), tachycardia (heart rate ≥90 bpm), and age ≥70 years. We converted these variables into a points system to create the ALT-70 cellulitis score as follows: Asymmetry (3 points), Leukocytosis (1 point), Tachycardia (1 point), and age ≥70 (2 points). With this score, 0-2 points indicate ≥83.3% likelihood of pseudocellulitis, and ≥5 points indicate ≥82.2% likelihood of true cellulitis.

Limitations

Prospective validation of this model is needed before widespread clinical use.

Conclusion

Asymmetry, leukocytosis, tachycardia, and age ≥70 are predictive of lower extremity cellulitis. This model might facilitate more accurate diagnosis and improve patient care.

Section snippets

Selection criteria

This study used the same cohort of patients used in our previous work, in which we performed a retrospective cross-sectional chart review of all patients presenting to and admitted through the ED of a large urban hospital with a diagnosis of lower extremity cellulitis between June 2010 and December 2012.9 Patients were identified by using the Research Patient Data Registry (RPDR), a clinical data registry of all patients within the Partners Healthcare system. Information stored within the RPDR

Patient characteristics

A total of 840 patient encounters of presumed cellulitis were identified, of which 259 met inclusion criteria (Fig 1); 581 patients were excluded from our analysis: 164 patients had skin lesions involving locations other than the lower extremities; 115 patients did not present directly to the ED (they transferred from outside the ED or another hospital); 110 patients had lesions associated with abscesses, penetrating trauma, burns, osteomyelitis, diabetic ulcers, or hardware; 108 patients did

Discussion

In our study, we found that asymmetry (unilateral leg involvement), leukocytosis, tachycardia, and age ≥70 years are predictive of lower extremity cellulitis. Using these 4 criteria, we developed the ALT-70 cellulitis scoring system as a fast and straightforward tool to aid in distinguishing patients with true cellulitis (c-statistic = 0.752). In our cohort, patients with an ALT-70 cellulitis score below 3 have a ≥83.3% likelihood of pseudocellulitis, and the diagnosis of cellulitis should be

References (27)

  • A.K. Venkatesh et al.

    Variation in US hospital emergency department admission rates by clinical condition

    Med Care

    (2015)
  • A. Dupuy et al.

    Risk factors for erysipelas of the leg (cellulitis): case-control study

    BMJ

    (1999)
  • N.J. Levell et al.

    Severe lower limb cellulitis is best diagnosed by dermatologists and managed with shared care between primary and secondary care

    Br J Dermatol

    (2011)
  • Cited by (40)

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

      2022, Journal of Emergency Medicine
      Citation Excerpt :

      The skin is comprised of several layers that form a barrier protecting the body from infection (1,3). Any disruption of the cutaneous barrier provides a site for normal skin flora and other bacteria to enter the dermis and subcutaneous layers of the skin, which can prompt an inflammatory response consisting of neutrophil recruitment and infiltration into the affected areas and cytokine production (1,3,4,32). In cases of nonpurulent cellulitis, a small number of bacteria and a robust inflammatory response most commonly result in a localized infection (1,3,4,32).

    • Cellulitis

      2021, Infectious Disease Clinics of North America
      Citation Excerpt :

      Laboratory testing is not necessary for uncomplicated cellulitis but may be useful for evaluating the severity of illness. Leukocytosis is reported in 30% to 50% of patients presenting to the emergency department or admitted to the hospital with cellulitis.29–32 Inflammatory markers often are elevated, but this is a nonspecific finding.29–31

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

      2021, Infectious Disease Clinics of North America
      Citation Excerpt :

      In patients with darker skin tones, erythema may be more subtle and therefore difficult to perceive (Fig. 2).5 It is a well-demarcated, irregularly bordered superficially spreading skin infection without an underlying collection of pus, and it is typically unilateral.6,7 It is often caused by streptococci, which sometimes reside in the interdigital toe spaces.6

    View all citing articles on Scopus

    Dr Raff and Dr Weng contributed to this work equally.

    Funding sources: None.

    Conflicts of interest: None declared.

    Reprints not available from the authors.

    View full text