What are the odd marks on this nurse’s nails?
28 year old, otherwise healthy nurse has multiple white marks on her nails. She says that she has noticed them, off and on, over her life and has also noticed them in several patients, mostly children, but also in adults.
What is your diagnosis?
Leukonychia Punctata appear as small white spots on the nails. Picking and biting of the nails are a prominent cause in young children and nail biters. In most cases, when white spots appear on a single or a couple of fingers or toes.
The most common cause is mild trauma to the base (matrix) of the nail. When this is the case, white spots disappear in 4-6 months, as the nails grow out. They are of no medical consequence.
Other types of white nails include leukonychia totalis (Terry’s nails) commonly seen in liver disease and Mee’s lines, which 2 white transverse bands associated with arsenic poisoning.
Punctate Leukonychia is characterized by white spots 1-3 mm in diameter occurring singly or in groups almost exclusively on finger nails. They are usually due to repeated minor trauma to the matrix. The evolution of the spots is variable; appearing generally on contact with the cuticle, they grow distally with the nail. Approximately half of them disappear as they migrate towards the free edge. This is believed to prove that parakeratotic cells are capable of maturing and losing their keratohyalin granules to produce keratin, even though they have been without a blood supply for many months. Some white spots enlarge, while others appear at a distance from the lunula, suggesting that the nail bed is participating by incorporating groups of nucleated cells into the nail. A similar process could explain the exclusively distal leukonychia which occasionally seen. A local or general fault in keratinization is not the only cause of punctate leukonychia; infiltration of air, which is known to occur in cutaneous parakeratoses, was for a long time believed to play a part. Disturbance of the nail plate’s highly organized keratin fibre system alters its transparency and makes it look white. This is evidence by polarization microscopy, as most clinically white spots lose their birefringence.
Charles E. Crutchfield III, MD
Clinical Adjunct Associate Professor of Dermatology
University of Minnesota Medical School
Medical Director, Crutchfield Dermatology
- Reference: Punctate Leukonychia - A Text Altas of Nail Disorders Techniques in investigation and diagnosis. - Robert Baran, Rodney PR Dawber, Eckart Haneke, Antonella Tosti, Ivan Bristow