A paronychia is an infection around the nail. Many organisms can cause a paronychia. This particular case is caused by the yeast-like organism Candida. Note the inflammation (red, swollen area) at the base of the nail and the changes that are apparent in the nail itself.

Nails may exhibit many different abnormalities. In the condition known as koilonychia, the nails are flattened and have concavities. This condition may be associated with iron deficiency.

In onycholysis the nails become loose. They may even detach from the nail bed. When not held firmly in place, the nails are rapidly damaged and debris collects beneath them.

White nail syndrome may also be called leukonychia. Leukonychia can occur with arsenic poisoning, heart disease, renal failure, pneumonia, or hypoalbuminemia.

Yellow nail syndrome is characterized by yellow nails that lack a cuticle, grow slowly, and are loose or detached (onycholysis). Yellow nail syndrome is most commonly associated with lung disorders, and with lymphedema.

Internal diseases and nutritional deficits can cause changes in the appearance of the nails.

Yellow nails are seen in the 'yellow nail syndrome' in which there is thickening and yellow to yellow-green discoloration of all nails. Lymphedema, especially of the ankles, and compromised respiration may be present. The nails may also be over-curved both transversely and longitudinally. Lunulae and cuticles may also be lost.

Like the skin, the fingernails are a reflection of a person's state of health. Low levels of zinc and iron as well as thyroid problems can cause brittle nails. However, brittle nails are often a normal result of aging.