Xanthomas are symptomless yellow firm nodules usually found over bony elbows, knees and heels. Sometimes, the appearance may be as pin-head sized yellow lumps, appearing in crops over the buttocks (eruptive xanthomas).

Diabetics often suffer from high lipid (cholesterol and triglycerides) levels in the blood. This causes fats to be deposited in the skin and presents as xanthomas.