Fungal infections may affect the nails, body folds, genital regions, and feet. The darkening and thickening of body folds due to insulin resistance, called acanthosis nigricans, may be early symptoms of diabetes. Diabetic dermopathy, damage to small blood vessels of the skin, may cause small, brown spots on the legs.Granuloma annulare are red, circular or arc-shaped lesions due to changes in the collagen of the skin. Click an image below to get diabetes information and learn more about early symptoms of diabetes.sually associated with a fungal (Candidal) or bacterial (Staphylococcal) infection, those…. Diabetic Dermopathy Diabetic dermopathy, also known as shin spots or pigmented pretibial patches, is a skin condition usually found on the lower legs of people with diabetes.