On a toe, the first difficulty is simply seeing it. Check your feet and legs every day. Check the tops and bottoms, ankles, heels, and between your toes. Look for changes in color and red or sore areas. Between the toes is the part most often skipped, and it matters, because wounds may appear on legs, ankles, toes, and between toes.
The second difficulty is that the usual first warning may not come. Diabetic ulcers are often painless, because of decreased feeling in the feet. A toe wound that does not hurt is not a reassurance.
The signs to check for are the ones for any wound caused by poor blood flow or diabetes: redness, increased warmth, or swelling around the wound; more drainage than before, or drainage that is yellowish or cloudy; bleeding; odor; fever or chills; and increased pain. For a diabetic foot ulcer, add one more that you feel rather than see — increased firmness around the wound.
Color is its own warning on a toe, separate from any sign of infection. Contact your provider if your foot ulcer is very white, blue, or black. Ulcers from poor blood flow can be dark red, yellow, gray, or black sores, and when the leg is raised it turns pale and cool to touch.
Toes sit at the end of the supply line, which is why they are a common site for wounds caused by reduced blood flow. A toe wound with new color, coldness or odor is worth a call rather than a week of watching.