Top of feet itchy is a sign of diabetes?

Not necessarily: Itching can be from dry skin, friction, fungus etc doesnt have to be from diabetes.

More like dry skin: Dry skin may be itchy with or without the diabetes present. General skin care is advised, but may need to watch out for skin fungus. I suggest you have it looked at by a physician.

Many possible causes: There are many things that could cause the skin to itch. Several types of inflammatory conditions of the skin, allergic reactions, and sometimes bacterial, viral or fungal infections can cause rashes on the skin. Insect bites can also be the cause of a rash on the skin. Have it evaluated by a professional and get the appropriate treatment.