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.
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.
Lyme disease is a bacterial infection transmitted by a tick Lyme disease was first recognized in 1975 after researchers investigated why unusually large numbers of children were being diagnosed with juvenile rheumatoid arthritis in Lyme, Connecticut and two neighboring towns.
Lichen striatus. This is a common and benign self-limited childhood dermatosis that is easily diagnosed from its classic appearance. Onset is usually between the ages of 3 and 10 years, and it is rare in young infants, adolescents, and adults. The lesions consist of pink, flesh-colored, or slightly hypopigmented flat-topped papules that evolve in a linear array following lines of Blaschko. The linear course of the papules may eventually traverse the major part of an extremity. The area of involvement is often noted to become wider as it advances and may even include the nails.