Repeated cellulitis in the foot can occur due to diabetes, poor circulation, fungal infection between the toes, swelling, obesity, or skin injury rather than just ?low immunity.? Since your doctor mentioned diabetes risk, you should get blood sugar tests such as fasting sugar and HbA1c. Cellulitis usually requires antibiotics such as Amoxicillin and Clavulanate or other antibiotics prescribed based on severity. To reduce recurrence, keep the feet clean and dry, treat any fungal infection, avoid barefoot walking, control weight and blood sugar, and manage swelling if present. There is no specific medicine that permanently ?boosts immunity,? but proper nutrition, sleep, exercise, and diabetes control are important. Please consult a physician for evaluation and the correct antibiotic treatment during each episode.