Erysipelas is an acute streptococcal skin infection, primarily affecting the lower limbs and easily diagnosed. In 2000, the French expert consensus conference validated oral amoxicillin at 3 to 4.5 gr per day for 10 to 20 days as a standard treatment, despite the lack of full market approval for erysipelas treatment. In practice, general practitioners (GPs) typically prescribe amoxicillin for around 10 days. In 2019, the Haute Autorité de Santé (HAS), one of the national French Health Authorities, recommended a 7-day antibiotic course for erysipelas, while no RCT was available. Reducing the length of antibiotic courses during acute infections is challenging but necessary to lower therapeutic costs, reduce the risk of bacterial resistance, and improve patient adherence to treatment.

This RCT aims to validate the use of a short course, specifically 5 days, of oral amoxicillin at 50 mg/kg to treat erysipelas, demonstrating its non-inferiority compared to the standard course. The primary objective is to show that a short course (5 days) of amoxicillin at 50 mg/kg is non-inferior to the usual course (10 days) in achieving complete erysipelas remission by day 12 ± 2. The primary end point will be confirmed by a central independent committee, blinded to the intervention received, using photos and clinical data.

Inclusion Criteria:

• Patients ≥ 18 years

• Affiliated to a social security scheme

• Who have given written consent according to local regulatory requirements after the nature of the study has been explained to them, and prior to any protocol specific procedures being performed,

• Clinical signs of lower limbs erysipelas ≤ 5 days defined as:

  o Warmth, erythema, edema (induration of the skin and/or subcutaneous tissue) and/or pain (NRS≤8)

• Shiver, feverish sensation or fever experienced by the patient ≤ 5 days or fever measured by the physician ≥ 38°C

• Severity score ≥ 3 scored on three criteria: edema, erythema, pain with the following scales (0= none, 1=moderate, 2=severe)

• Absence of erysipela ≤ 12 months

• Absence of blisters

• Absence of solid purpura (purple tablecloth not erasing at vitro-pressure)

• Absence of cutaneous necrosis

• Absence of crepitation (crepitation = perception identical to that of cutaneous emphysema

Exclusion Criteria:

• Allergy to ß lactam, fructose intolerance
• Weight < 40 kg or > 105 kg
• Use of oral antibiotic within 5 days (excluding one or two antibiotic intake ≤ 24 hours)
• Erysipela/Cellulitis requiring hospitalization
• Bilateral erysipela
• Abscess
• Lymphedema requiring permanent contention
• Animal bite ≤ 7 days
• HIV positive
• Patient with comorbidity: known active hepatitis, chronic kidney failure or hepatocellular insufficiency
• Patient unable to temporarily stop a long-term treatment as antibiotics or corticosteroids, or NSAIDs
• Patient under immunosuppressive or oncologic treatments ≤ 6 months
• Pregnant women or breastfeeding
• Patient under guardianship or curatorship, legal protection or protection of justice
• Participation in other Clinical Trial, interventional study, investigational study or performance study Any medical, mental, psychological or psychiatric condition considered by the investigator as compromising patient completion or understanding of the study