Study of New Antibiotic Regimen for the Treatment of Uncomplicated Cellulitis in Emergency Department Patients

Randomized Trial of Trimethoprim-Sulfamethoxazole Versus Placebo Added to Standard Treatment of Uncomplicated Cellulitis in Emergency Department Patients

The primary aim of this study is to quantify the effectiveness of Bactrim as additional therapy for the treatment of uncomplicated cellulitis in adults, by comparing: standard therapy plus Bactrim, versus standard therapy plus placebo.

The primary hypothesis of this study is that, in light of increasing CA-MRSA prevalence, subjects treated with standard therapy plus Bactrim will have higher cure rates than those treated with standard therapy plus placebo.

Inclusion Criteria

• Must have cellulitis as defined here:

  1. Definition A (preferred definition):

     Recent onset of soft tissue erythema, considered by the treating clinician to be bacterial in origin, and associated with signs of infection that include at least two of the following: pain, swelling, warmth, fever, lymphangitis, induration, or ulceration.

  2. Definition B (ONLY for darkly-pigmented subjects who cannot use Definition A):

     Recent onset of soft tissue color change, pain, or swelling, considered by the treating clinician to be bacterial in origin, and at least one of the following: warmth, fever, induration, or ulceration

• Clinical (non-research) attending physician agrees with treatment with cephalexin until 3 days after all symptoms gone, using our weight-based dosing

• Responsible clinical attending physician comfortable with adding trimethoprim-sulfamethoxazole vs. placebo to the above

• Subject understands the study and signs written informed consent.

• Subject agrees to drink at least 1 liter of fluid per day.

• Subject will commit to all follow-up appointments

Exclusion Criteria:

• Age < 12 months or weight <15 kg
• Current skin infection has already been treated
• Allergy to sulfa drugs
• History of severe allergic reaction to penicillin (defined as anaphylactoid reaction, angioedema, bronchospasm)
• Current use of any antibiotic (other than topicals)
• Diabetes mellitus
• Cellulitis complicated by underlying peripheral vascular disease
• Renal insufficiency, defined as patient report, clinical suspicion, or creatinine>1.3 or EGFR<60 on the last-available set of chemistry results in our computer system
• Hospital admission required
• Presence of > 1 cc of purulent discharge at any time
• Cellulitis involving an indwelling vascular, enteric, or urinary catheter
• Immunocompromise of any etiology
• Pregnancy
• Breast feeding
• Facial cellulitis (infection is above the clavicles)
• Cellulitis associated with marine or freshwater injury, or animal or human bite. (Insect bites not excluded.)
• History of glucose-6-phosphate dehydrogenase deficiency
• Taking coumadin (warfarin), methotrexate, cisapride, phenytoin (dilantin), digoxin, or dofetilide
• Known megaloblastic anemia due to folate deficiency.