ALT-70 Score: Discriminates between cellulitis and pseudocellulitis. Reduces unnecessary antibiotic use and hospital admissions for lower limb redness.
Clinical criteria
Diagnostic Probability
Low Probability (0)
Approx. 80% chance of pseudocellulitis. Consider alternative diagnoses (e.g., stasis dermatitis).
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Adult patients presenting with presumed lower-limb cellulitis
Differentiating true cellulitis from pseudocellulitis (e.g., stasis dermatitis, lipodermatosclerosis)
Avoiding inappropriate antibiotic prescribing in the Emergency Department
Section 2
Formula & Logic
Scoring Components
Asymmetry (Unilateral) (3 pts)
Leukocytosis (WBC ≥ 10k) (1 pt)
Tachycardia (HR ≥ 90) (1 pt)
Age ≥ 70 years (2 pts)
Interpretation
Score ≤ 2
Low probability of cellulitis (~80% chance of pseudocellulitis). Consider alternative diagnosis.
Score 3–4
Intermediate probability. Clinical judgment or dermatology/ID consult indicated.
Score ≥ 5
High probability of cellulitis (~80% probability).
Section 3
Evidence Appraisal
Validation
Development and validation of a clinical prediction rule for lower extremity cellulitis.
Raff AB et al. • JAMA Dermatol.. 2017;153(5):435-439. Validated tool showing high external validity for ED-based diagnosis.
