The Particulars: Early treatment response has emerged as a reliable predictor of outcomes following the initiation of antibiotics for cellulitis. However, studies have not characterized early treatment response well in cellulitis. Little is known about predictors of response, speed of the response, or its relation to late treatment failure.

Data Breakdown: A study of hospital patients with cellulitis found that those who had a local response at day 1 of antibiotic treatment (42%) were more likely to have a decline in leukocyte count of 20% or greater at day 1 (63%) than patients with a slower response (37%). By day 2 of antibiotic treatment, 82% of patients had a local response, 59% of febrile patients were afebrile, and 73% had a 20% or greater decline in C-reactive protein level. Symptom duration of 2 or more days prior to admission was an independent predictor of local response at day 1.

Take Home Pearls: The majority of cellulitis patients appear to show clinical and biochemical signs of improvement within 1 day of antibiotic treatment. Symptom duration prior to treatment appears to be an independent predictor of response time. Factors not related to etiology or antibiotic choice should considered when assessing early treatment response.