Lymphedema is a chronic and progressive disease of the lymphatic vessels which affects about 300 million people worldwide. Patients may experience recurrent soft tissue infection of the limb affected by lymphedema, in terms of erysipelas, lymphangitis or cellulitis. No previous study has ever investigated the possible role of the gut microbiota in the genesis of acute infectious/inflammatory episodes in these patients. Our hypothesis is that lymphedema patients with recurrent soft tissue infections are characterized by pro-inflammatory changes in the microbiota.

Inclusion Criteria (Group A):

• 18-85 years
• primary or secondary, upper or lower limb lymphedema, I-II-III stage ISL
• at least 3 episodes of soft tissue infection in an year, in the last 2 years
• consent to participate in the study

Inclusion Criteria (Group B):

• 18-85 years
• primary or secondary, upper or lower limb lymphedema, stage I-II-III (ISL)
• no episodes of soft tissue infection in the last 2 years
• consent to participate in the study

Exclusion Criteria:

• No compliance to perform limb compression and skin hygiene
• Antibiotic therapy in the last 15 days
• Diabetes mellitus
• Immunodeficiency
• Ongoing neoplastic pathology
• Taking immunosuppressive drugs
• Unavailability to follow-up for at least 24 months post-enrollment.

A prospective observational cohort study will be conducted on patients with limb lymphedema, clinical stage I, II and III according to the International Society of Lymphology (ISL), followed by the Plastic Surgery Unit of the University Polyclinic A. Gemelli IRCCS. According to the positive or negative history for recurrent soft tissue infectious episodes, patients will be divided into two homogeneous groups for demographic and clinical characteristics (Groups A and B).