However, there is a less well-known symptom that can appear on the skin.
According to the Cleveland Clinic, diabetes-related dermopathy is a potential complication of both type 1 and type 2 diabetes.
The patches commonly appear on the shin, although can be found on any part of the body. And they can be pink, red or brown in colour.
The clinic explains: “Diabetes-related dermopathy (often called ‘shin spots’) is a fairly common skin condition that affects people who are living with diabetes, including type 1 diabetes and type 2 diabetes.
“Diabetes-related dermopathy looks like small, round pink, reddish or brown patches on your skin. They can look like scars and be indented.
“They’re generally one centimetre to 2.5 centimetres in size. The patches are harmless and don’t itch, ooze liquid or cause pain.”
Other distinguishing features of the patches include being:
- Round or oval
- Slightly indented into your skin and/or somewhat scaly
- Bilateral, meaning they appear on the skin of both of your legs or both of your arms at the same time.
The patches can appear for months at a time and according to the American Diabetes Association they are often “mistaken” for age spots.
It is not known exactly what causes diabetes-related dermopathy, however, researchers believe it could be caused by prior trauma to the skin.
This could be due to an injury or extreme heat of cold, especially in people with neuropathy – a type of nerve damage that’s caused by chronic high blood sugar.
It is also more common among older people and those who have had diabetes for a long time.
A paper, published in the British Journal of Diabetes and Vascular Disease in 2014, detailed how it occurs in up to 55 percent of patients with diabetes.
“Diabetic dermopathy is a term used to describe the small, round, brown atrophic skin lesions that occur on the shins of patients with diabetes,” it says.
“The lesions are asymptomatic and occur in up to 55 percent of patients with diabetes, but incidence varies between different reports.”
Other symptoms of diabetes include:
- Feeling very thirsty
- Urinating more frequently than usual, particularly at night
- Feeling very tired
- Weight loss and loss of muscle bulk
- Itching around the penis or vagina, or frequent episodes of thrush
- Blurred vision.
If you experience any of the symptoms of diabetes you should speak to your GP.