title: A predictive model for diagnosis of lower extremity cellulitis: A cross-sectional study.
abstract: 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.
  
  
  CONCLUSIONS
  Prospective validation of this model is needed before widespread clinical use.
  
  
  CONCLUSIONS
  Asymmetry, leukocytosis, tachycardia, and age ≥70 are predictive of lower extremity cellulitis. This model might facilitate more accurate diagnosis and improve patient care.
authors.affiliation: Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Adam B
authors.initials: AB
authors.lastname: Raff
authors.affiliation: Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Qing Yu
authors.initials: QY
authors.lastname: Weng
authors.affiliation: Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Cohen
authors.affiliation: Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Nicole
authors.initials: N
authors.lastname: Gunasekera
authors.affiliation: Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Jean-Phillip
authors.initials: JP
authors.lastname: Okhovat
authors.affiliation: Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Vedak
authors.affiliation: Department of Public Health Sciences, Loyola University, Chicago, Illinois.
authors.forename: Cara
authors.initials: C
authors.lastname: Joyce
authors.affiliation: Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Daniela
authors.initials: D
authors.lastname: Kroshinsky
authors.affiliation: Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts. Electronic address: Amostaghimi@bwh.harvard.edu.
authors.forename: Arash
authors.initials: A
authors.lastname: Mostaghimi
mesh_terms: D000367:Age Factors; D000368:Aged; D016470:Bacteremia / Q000209:etiology; D002481:Cellulitis / Q000150:complications / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D004630:Emergencies; D005260:Female; D006801:Humans; D007866:Leg; D007964:Leukocytosis / Q000209:etiology; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013610:Tachycardia / Q000209:etiology
keywords: cellulitis; diagnosis; diagnostic model; lower extremity cellulitis; misdiagnosis; predictive model; pseudocellulitis