Leukonychia totalis. This is a rare nail disorder that is inherited in autosomal dominant fashion. The color of normal nail plates beyond the lunulae is largely pink from the blood in the blood vessels of the nail bed. The whiteness shown here is due to an abnormality in the nail plate. The nails may also be brittle.
Juvenile xanthogranuloma. This is a common and completely benign cutaneous nodule. Typically, a juvenile xanthogranuloma is firm and dome-shaped. At first, the lesion is reddish, but develops a fairly typical orangebrown hue over time. Most juvenile xanthogranulomas are located on the head or neck, as pictured in these two infants, but the lesions sometimes occur on the trunk or extremities. They may be present at birth, but most develop during the first year of life. Juvenile xanthogranuloma is not associated with abnormalities in serum cholesterol or triglycerides, and the individual lesions undergo spontaneous involution, usually over a period of 1–2 years. A diagnostic biopsy analysis is sometimes needed, but surgical intervention beyond this is certainly not required. Multiple juvenile xanthogranulomas on the skin may be accompanied by intraocular lesions. For this reason, the physician must pay careful attention to the examination of the eyes.
Leukonychia striata. The horizontal white streaks pictured here are the result of abnormal keratinization of the nail plate. The tendency toward leukonychia striata is sometimes inherited in an autosomal dominant fashion. In other cases, it can be attributed to vigorous manicuring, to trauma, or to a wide variety of systemic illnesses. In many patients, there is no obvious cause, and the streaks resolve spontaneously.