An 8-year-old boy has had a rash on his distal fingers for
a few months, and the cuticles are becoming progressively
worn. The boy constantly picks at the dried skin, causing
frequent bleeding. At one point, the skin became infected,
for which a course of an antibiotic was given. The boy is
otherwise healthy and does not take any medications. Examination
reveals erythematous and scaling plaques around the cuticles
and on the distal fingers. Multiple small pits can be seen
on the fingernails, and the distal nail is slightly separated
from the nail bed. The remainder of the examination is unremarkable.
The patient has psoriasis. Nail abnormalities associated
with psoriasis are seen in up to 55% of adults and 13% of
children. Such findings may be the only manifestation of psoriasis
and may include pitting, onycholysis (detachment of the nail
plate from the nail bed), discoloration of the nail bed, subungual
hyperkeratosis, and splinter hemorrhage. Chronic paronychia
may occur in conjunction with nail psoriasis.
The differential diagnosis for these findings includes contact
dermatitis and onychomycosis. Appropriate cultures and testing
can aid in the diagnosis. Psoriatic nails are the most difficult
cutaneous feature of psoriasis to treat. Ultra-high potency
steroid ointments may be beneficial. Steroid lotions-applied
under the nail-may also be effective. On occasion, intralesional
injections of steroid have been used with limited success.
Dr. LaDuca is a resident and Dr. Mercurio is an assistant
professor in the department of dermatology at University of Rochester-Strong
Memorial Hospital in Rochester, New York.
