The cause is not certain as it is the result of more than one disease process. Genetic factors, teratogens, compromised vasculature to the skin, and trauma are all implicated [1, 2].
Maximum tensile force during the development of scalp hair whorl is implicated for the scalp lesion. Early rupture of amniotic membrane forming amniotic bands may also be responsible [1].
In very few reports are histological details available; histological features vary depending on the depth of aplasia and duration. Ulcers are seen at birth. After healing, the epidermis appears flattened with proliferation of fibroblasts within a connective tissue stroma. Total absence of the epidermal appendages remains a characteristic feature [6].