ToolsCalculators
ALT-70 score for cellulitis
Distinguishes true lower-extremity cellulitis from its mimickers (pseudocellulitis).
ALT-70 score for cellulitis
Asymmetry (unilateral leg involvement)
Cellulitis is almost always one-sided; bilateral leg redness favours a mimicker such as venous stasis dermatitis or lipodermatosclerosis.
Leukocytosis (WBC ≥ 10,000/µL)
Tachycardia (heart rate ≥ 90 bpm)
Age ≥ 70 years
Result0 points
0-2 points: pseudocellulitis (a cellulitis mimicker, e.g. venous stasis dermatitis, lipodermatosclerosis, DVT) is likely - this range predicted a mimicker in ≥83% of the derivation cohort.
- Asymmetry
- 0
- Leukocytosis
- 0
- Tachycardia
- 0
- Age ≥ 70
- 0
When to use
- Adult presenting to the emergency department with suspected lower-extremity cellulitis, to gauge how likely the diagnosis is before committing to antibiotics or admission.
- Not validated for cellulitis elsewhere on the body, or in patients with a clear alternative explanation (e.g. known abscess, ulcer, burn).
Formula
Points: asymmetry (unilateral leg involvement) 3; leukocytosis (WBC ≥ 10,000/µL) 1; tachycardia (heart rate ≥ 90 bpm) 1; age ≥ 70 years 2. Total range 0-7.
Pearls and pitfalls
- Derived and cross-sectionally validated at a single US academic centre; a later cohort found predictive value was maintained when re-applied at 24 and 48 hours.
- Intended to reduce misdiagnosis of pseudocellulitis, which drives unnecessary antibiotics and admissions.
References
- Raff AB, Weng QY, Cohen JM, et al. A predictive model for diagnosis of lower extremity cellulitis: A cross-sectional study. J Am Acad Dermatol. 2017;76(4):618-625.
- Singer S, Li DG, Gunasekera N, et al. The ALT-70 cellulitis model maintains predictive value at 24 and 48 hours after presentation. J Am Acad Dermatol. 2019;81(6):1252-1256.