A diabetes rash is caused by reduced blood flow to the skin, according to Healthline. Decreased blood circulation may lead to changes to the skin’s texture, appearance and ability to heal.
An estimated one-third of diabetics suffer from skin problems. A diabetic may experience a reduced ability to sweat and an increased sensitivity to temperature due to the damage to the skin’s vascular endothelial cells. Some glucose-lowering medications may increase the risk of developing diabetes-related skin complications, notes Healthline.
Bacterial infections of the skin -- the most common are staphylococcus and streptococcus -- may increase in size, number and frequency if the diabetic's blood glucose is repeatedly high. Serious bacterial infections can cause carbuncles, requiring medical attention. Healthline explains that fungal infections are also common in type-2 diabetes patients, especially if blood glucose is not well-controlled. Specifically, the fungus Candida albicans presents itself in red, itchy, swollen skin surrounded by blistering or dry scales.
Healthline cites a number of other skin conditions specific to type 2 diabetes, including diabetic dermopathy, necrobiosis lipoidica diabeticorum, atherosclerosis, disseminated granuloma annulare, acanthosis nigricans and diabetic blisters. These conditions are usually related to changes in the small blood vessels that supply nutrition to the skin tissues, and they are seen more frequently in long-term diabetes that is not being managed properly.