The ALT-70 is a clinical prediction rule for cellulitis. It is used to differentiate cellulitis from pseudocellulitis in adult patients presenting with lower extremity redness. The acronym ALT-70 stands for Age (over 70), Lesion characteristics (asymmetry, well-demarcated border), Temperature (37.9°C or higher), and White blood cell count (more than 10,000 cells/mm³). Each of these four factors is assigned a score, and the total score is used to predict the likelihood of true cellulitis. This calculator is particularly useful in emergency departments and outpatient settings to guide treatment decisions and avoid unnecessary antibiotic use. It should not be used in patients with known skin infections other than cellulitis, or in patients with skin changes due to chronic conditions like venous insufficiency or lymphedema.
Reference
Sean Singer, David G Li, Nicole Gunasekera et al. The ALT-70 cellulitis model maintains predictive value at 24 and 48 hours after presentation. J Am Acad Dermatol. 2019 Dec;81(6):1252-1256.
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