A person’s nails can say a lot about their overall health, while changes to the nails may suggest an underlying issue that needs treatment, such as nail psoriasis or Raynaud’s disease.

The curving of the nails does not always indicate a cause for concern, but it may be a good idea to consult a doctor. If changes to the nails accompany other symptoms, it is important to seek care promptly.

In this article, we describe types of nail curving and other nail changes that may need monitoring. We also explore some possible causes.

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Koilonychia (spoon nail). iweevy/Shutterstock

Some or most of the nail may curve outward, away from the nail bed. For example, a person may have one of the below conditions.

Spoon nails

With spoon nails, the nails become so soft and curved that they can hold a droplet of water. Doctors often refer to this as koilonychia.

This issue may occur in newborns, but it may resolve without needing treatment. In other cases, and in people of other ages, koilonychia can indicate health issues, such as iron-deficiency anemia.

Nails that curve at the tips

This involves the thickening of the tissue underneath the nail, causing the fingertips to become rounded and the nails to curve over them.

Doctors believe this results from increased blood flow to the fingertips. It can run in families and may be harmless, but it may be due to a health condition, especially if it occurs later in life.

Nails that curve around the sides

Nails that curve far inward at the sides are called ingrown nails. This condition may affect the toenails and be due to wearing shoes that are too tight, particularly in the toe box.

Ingrown nails may also result from cutting the nails improperly. In some cases, treatment may involve removing part or all of the nail.

Other nail issues

The nails may become crumbly or brittle due to:

Small dents and pits may also appear in the nails, which may result from:

Curving of the nails sometimes stems from an underlying health issue. This may be temporary, such as a fungal infection, or chronic, such as psoriasis. We explain some of the common causes below.

Iron deficiency anemia

Iron helps maintain healthy cells, skin, hair, and nails, while an iron deficiency may be due to:

  • an underlying health issue
  • pregnancy
  • heavy periods
  • a diet low in iron

Some common symptoms besides curved nails may include:

  • paleness
  • fatigue
  • weakness
  • a rapid heartbeat
  • a sensation of pounding in the ears
  • headaches
  • hair loss

Treatment for iron deficiency anemia may involve:

  • Eating more iron-rich foods: These include beef, pork, lamb, liver, broccoli, kale, collard greens, pinto beans, and black-eyed peas.
  • Taking a high-dose supplement: A doctor can recommend or prescribe a sufficiently high dosage.
  • Intravenous supplementation: A healthcare professional may recommend this for people who are unable to pass iron through their gastrointestinal tract.

Nail psoriasis

About 90% of people with psoriasis develop the condition on their nails at some point. Besides curving, symptoms may include thickening and shallow or deep holes in the nail.

Treatment may involve:

  • topical creams or ointments
  • light therapy
  • injections
  • oral medications

Raynaud’s disease

This rare disorder affects the arteries, causing them to periodically narrow and block blood flow to specific body parts, usually the fingers or toes.

As a result, the fingers and toes may:

  • turn pale or white, then bluish
  • feel numb, cold, or painful
  • redden
  • throb, burn, tingle, or feel numb

Treatment for Raynaud’s may involve managing stress or taking medication, or rarely, undergoing surgery. However, there is no cure.

Hemochromatosis

This genetic disorder causes the body to absorb too much iron from the diet. While a person typically has around 1 gram (g) of iron in their body at any time, this condition can cause a buildup of 5 grams or more.

Besides curved nails, symptoms may include:

  • hair loss
  • skin discoloration
  • weight loss
  • early menopause
  • joint pain
  • abdominal pain
  • liver dysfunction
  • sexual dysfunction
  • weakness and lethargy

Hemochromatosis can damage the liver, heart, and pancreas. Without treatment, people may show signs of iron toxicity in their 30s, and the disease may be fatal.

Management involves the regular removal of blood until iron levels are within a normal range.

Dietary changes may also help. Learn more here.

Systemic lupus erythematosus

This chronic disease can cause trigger inflammation and pain in any area of the body. About 1.5 million people in the United States have a form of lupus, while systemic lupus erythematosus is the most common type.

Symptoms of this autoimmune disorder can flare up and recede. Beyond curvature of the nails, they can include:

  • fatigue
  • rashes
  • joint swelling or pain
  • fevers
  • sensitivity to sunlight or fluorescent light
  • lung problems

Treatment generally focuses on suppressing the immune system with medications.

It may be worth speaking with a doctor about persistent, noticeable changes to the nails. It is especially crucial for a person to consult with a healthcare professional if other symptoms are present.

A doctor will identify the underlying issue and advise on the best course of treatment.

Changes to the nails, such as curving, sometimes result from an underlying health issue requiring treatment. However, these changes are not always a cause for concern.

If curving of the nails occurs with other symptoms, a person should seek medical treatment.