Calcified nodules of the heel represent dystrophic calcification of the skin (calcinosis cutis) following trauma, mostly due to needle sticks during the neonatal period. Lesions occur in both normal infants and in high-risk neonates with a history of repeated heel sticks. It is believed alkaline phosphatase is released during the needle stick, leading to an altered local pH, with precipitation of calcium salts. Serum calcium and phosphate levels are normal.

Calcified nodules begin as small yellow-to-white nodules that slowly increase in size and migrate through the epidermis to the skin surface. Lesions typically appear between 4 and 12 months of age and often resolve spontaneously between 18 and 30 months. Most lesions are asymptomatic, but some may cause local irritation or pain.