Thigh Abscess After Off‑Label CGM Sensor Use in Uncontrolled Diabetes

A 49‑year‑old man with very high blood sugar developed a large infection on his thigh after placing a glucose sensor there. The sensor was not approved for that spot. He had tried the arm before but it kept falling off. Three days later a painful, red, swollen lump about the size of a credit card appeared at the insertion site.

Doctors cut open the abscess and gave him an antibiotic pill. Four days later the pain got worse and he could hardly walk. He needed a second drainage, wound packing, a topical antibiotic cream, and kept taking the pills. After the second procedure the wound started to heal.

Skin reactions from these sensors are usually mild, like a rash or irritation. Serious infections are rare, and none have been reported when the device is used in an unapproved area. This case shows that off‑label placement can lead to a real infection, especially when diabetes is not well controlled.

Pharmacists can help by teaching patients the correct places to put the sensor, watching for early signs of infection, and working with the care team to prevent problems.