Naproxen Versus Placebo as Adjunct Treatment of Cellulitis

Cellulitis is a painful bacterial skin infection commonly seen in Canadian emergency departments. Cellulitis has a negative impact on patients' quality of life and productivity. While this is a bacterial infection, there is evidence inflammation also contributes to the disabling symptoms of pain, redness and swelling. Some studies have suggested that a nonsteroidal anti-inflammatory drug (NSAID) such as naproxen in addition to antibiotics may control inflammation and speed recovery. However, these studies have had too few patients to tell if there is a true benefit. The investigators are proposing a randomized controlled trial of patients with cellulitis to compare oral naproxen (500 mg twice daily) plus oral antibiotics versus placebo plus oral antibiotics. The investigators will compare the proportion of patients who have an early clinical response (reduction in area of redness ≥20% at 72 hours), cure, treatment failure, adverse events, and hospital admission. If naproxen proves to be superior to placebo, this simple, low-cost intervention will speed time to recovery with less pain for patients, and may potentially reduce treatment failure and time missed from activities. The results of this trial will help inform future cellulitis treatment guidelines.

Inclusion Criteria: * adults (age ≥18 years) * diagnosed with cellulitis and * determined by the treating physician to be eligible for outpatient treatment with oral cephalexin Exclusion Criteria: These are appropriate exclusions according to eligibility for treatment with naproxen in clinical practice, and the investigators believe that relatively few patients will be excluded. The investigators will exclude participants for any of the following reasons: 1. Age \