About 50 percent of persons with active
psoriasis have psoriatic changes in fingernails and/or toenails. In
some instances psoriasis may occur only in the nails and nowhere
else on the body. Psoriatic changes in nails range from mild to
severe, generally reflecting the extent of psoriatic involvement of
the nail plate, nail matrix (tissue from which the nail grows), nail
bed (tissue under the nail), and skin at the base of the nail.
Damage to the nail bed by the pustular psoriasis can result in loss
of the nail.
Nail changes in psoriasis fall into
general categories that may occur singly or all together:
The nail plate is deeply pitted,
probably due to defects in nail growth caused by psoriasis.
The nail has a yellow to yellow-pink
discoloration, probably due to psoriatic involvement of the nail
White areas appear under the nail
plate. These are air bubbles marking spots where the nail plate is
becoming detached from the nail bed (onycholysis). There may be
reddened skin around the nail.
The nail plate crumbles in yellowish
patches (onychodystrophy), probably due to psoriatic involvement
in the nail matrix.
The nail is entirely lost due to
psoriatic involvement of the nail matrix and nail bed.
The following four photos illustrate
psoriatic changes in nails:
Psoriasis of fingernails.
Psoriasis of fingernails.
Onycholysis in psoriatic
Pustular psoriasis on
toenails and foot.
(Photos used with permission of the
American Academy of Dermatology
National Library of Dermatologic Teaching Slides)
Psoriasis of the nails can resemble
other conditions such as chronic infection or inflammation of the
nail bed or nail fold. Psoriasis of the toenails can resemble
chronic fungal infection of the nails.
A person with psoriatic nails should
avoid any injury - bumps, scrapes, etc. - that may trigger a
worsening of psoriasis (Koebner’s phenomenon). Nail psoriasis is
treated by the dermatologist as part of the overall treatment of the
Nail psoriasis is frequently associated
with psoriatic arthritis—which is discussed below.
Psoriatic arthritis is a
genetically determined autoimmune disease that occurs in less than
10 percent of persons with psoriasis. Its treatment often requires
consultation with a rheumatologist in addition to treatment of the
skin lesions by a dermatologist. Psoriatic arthritis is classified
with the disease grouping called seronegative spondyloarthropathies
which also includes ankylosing spondylitis, enteropathic arthritis,
and Reiter’s Syndrome. It occurs most frequently in psoriasis
patients whose disease is active, especially in persons with the
pustular type of psoriasis. Occasionally it appears in a person who
has no dermatologic signs or symptoms of psoriasis, in which case it
must be diagnosed by its unique laboratory test results. Psoriasis
of the fingernails and toenails is associated with a higher
incidence of psoriatic arthritis.
Symptoms of psoriatic arthritis
resemble those of rheumatoid arthritis, although the diseases are
otherwise quite different. Arthritis changes cause deterioration and
pain in small joints of the hands and feet, large joints of the legs
and spine, and tendons. Nonspecific foot pain or "tennis elbow" may
be an early symptom to appear and may be overlooked if not
associated with psoriatic skin or nail lesions.
Confirmation of a diagnosis of
psoriatic arthritis requires specific blood and serum tests to
differentiate it from conditions such as rheumatoid arthritis and
other autoimmune diseases.
Please see the
for information on the treatment of
A pediatric form of psoriatic arthritis
may appear as early as age 2 to 4 years in girls. A peak period of
pediatric onset is age 11 to 12 in both girls and boys. In children
the arthritis may appear several years prior to the onset of
psoriatic skin lesions; this may pose a problem in recognizing the
nature of the underlying disease, especially if there is no known
family history of psoriasis.
Although psoriatic arthritis and
psoriasis occasionally occur in the absence of a history of
psoriasis in the family, a genetic predisposition for psoriasis is
considered to be a necessary condition for development of psoriatic
arthritis. The evidence for inheritability is well established.
As in the case of psoriasis, an
environmental "trigger" may initiate the development of psoriatic
arthritis in a genetically predisposed person.
All content solely
developed by the American Academy of Dermatology
For an overview, visit
the AAD pamphlet
Psoriasis and Psoriatic Arthritis.