Loss of pigmentation can be a result of the absence of melanocytes as in vitiligo and halo nevi Vitiligo is a symmetric, patchy loss of pigmentation with a likely autoimmune etiology Hairs located in areas of vitiligo are often white Vitiligo can be associated with alopecia areata, pernicious anemia, Addison disease, hypothyroidism, diabetes mellitus, hypoparathyroidism, and other endocrine disorders Suppression of melanocytic pigment production can cause loss of pigmentation, as in postinflammatory hypopigmentation An example of this condition is the white patch of hypopigmentation and scaling often seen on the face, trunk, or extremities of children with atopic eczema The ash-leaf macule is a flat, hypopigmented (whitish) spot that is present in more than 90% of patients with tuberous sclerosis Hyperpigmentation In the neonatal period, hyperpigmented birth marks are relatively common Pigment deep in the dermis appears gray or blue at the surface of the skin Mongolian blue spots, now called dermal melanocytosis, are an example of this phenomenon ( Fig 69.17 ) The Nevus of Ota is dermal pigment in the distribution of the ophthalmic branch of the fifth nerve; this pigmentation can also involve the sclera and palate Patients with Nevus of Ota have a risk of glaucoma