Pediatric emergency medicine trisk 1347 1347
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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.
