These are disorders more likely to be seen in patients with diabetes compared to the general population. The best known example is

Necrobiosis lipoidica, a necrotising skin lesion most frequently found on the shins.

Granuloma annulare is a chronic skin disease presenting mainly in the limbs and consisting of reddish raised lesions arranged in rings.

Diabetic cheiropathy presents with thickened waxy skin on the hands.

Bullous diabeticorum presents with blisters.

Nonspecific diabetic vasculitis presents with purpura or a rash of purple spots in the skin.

Acanthosis nigricans is a typical browny black velvety lesion often found in the skin folds. When it is associated with diabetes it is called pseudo-acanthosis nigricans and it needs to be distinguished from the form referred to simply as acanthosis nigricans which is associated with some forms of cancer.