A 62-year-old diabetic man was evaluated for a chronic red and hyperpigmented papular eruption most dense on his shins and scattered on his thighs and forearms. Although pigmented pretibial patches, also known as diabetic dermopathy, are not specific for diabetes, they are found in 50 percent of diabetics. Lesions usually begin as flat topped dull red round or oval papules clustered on the shins. The thighs and forearms may also become involved. In time the papules develop scale, atrophy and hyperpigmentation, and lesions may become confluent particularly on the lower legs. Although the cause is unknown, pigmented pretiaibl patches may result from recurrent trauma in the setting of diabetic microangiopathy or venous insufficiency.
symmetric discrete and confluent red papules and patches with scattered central crusts and peripheral scale