“Koilonychia” is the medical term for “spoon nails,” in which your nails develop an indentation that makes them look cupped, like a spoon. Several health or environmental conditions can lead to koilonychia. It is not painful but can indicate an underlying health concern that needs treatment.

This article will describe the symptoms of koilonychia, what it looks like, what causes it, and how it can be treated.

Symptoms of Koilonychia

Koilonychia develops slowly, as the fingernails grow and take on a concave (cupped) shape, which gives them the name spoon nails. The indentation can be horizontal or vertical. You can sometimes put a drop of water onto the nail and it will not run out.

The nails also become thinner and softer. They may crack or separate from the nail bed.

Koilonychia usually affects the fingernails, but it can also develop in the toenails, depending on the cause.

Causes of Koilonychia

The most common cause of koilonychia is a lack of nutrients, often an iron deficiency. It’s also seen in people with iron storage problems such as hemochromatosis (excess iron, which can be inherited or due to blood transfusion).

Some of the medical conditions that can cause spoon nails are:

  • Diabetes
  • Heart disease
  • Psoriasis: A chronic autoimmune skin disorder
  • Lupus: An autoimmune inflammatory disorder
  • Lichen planus: A common condition in which an immune reaction affects the mouth, skin, and/or nails
  • Underactive thyroid (hypothyroidism)
  • Raynaud’s syndrome: A condition of restricted blood flow in the small blood vessels of the digits
  • Nail patella syndrome: A rare genetic condition with abnormalities in the nails, knees, elbows, and hips

You can also develop spoon nails from environmental factors. These include:

  • Frequent use of products made with petroleum (such as certain hair care products) or with hair-removal productsHigh altitude, which may inhibit nail growth due to reduced oxygenInjury to the nailMechanical stress to the nail

Spoon nails can also be an inherited condition, but this is very rare.

Medications That Can Cause Koilonychia

In some people, cancer treatments including chemotherapy or radiation treatment can cause spoon nails. Cancer treatment can have other effects on nails, but these tend to reverse when treatment is completed.

How to Treat Koilonychia

Treatment for koilonychia depends on the cause. If you have iron deficiency anemia, your healthcare provider can prescribe an iron supplement and address the underlying cause of your iron deficiency anemia.

If you have another medical condition, such as psoriasis or lupus, appropriate treatment for that condition may help reverse koilonychia. When spoon nails are due to environmental factors, reducing the exposure is important.

Talk to a healthcare provider before you try any home remedies for spoon nails, but keeping your nails clean and moisturized can help. You can also try a cuticle cream to stimulate growth.

It takes months for new, healthy nails to grow, but if the underlying cause is addressed, koilonychia can often be reversed unless it is genetic.

Are There Tests to Diagnose the Cause of Koilonychia?

Tests can help determine what’s causing koilonychia. These include checking for underlying conditions and blood tests for low iron or iron storage problems like hemochromatosis.

Depending on other symptoms, you may be examined or tested for lupus, psoriasis, diabetes, thyroid hormone levels, or other medical conditions.

When to See a Healthcare Provider

If you notice that you are developing koilonychia, see a healthcare provider. You may have an underlying medical condition that needs treatment.

Summary

Koilonychia is a condition of the nails, usually the fingernails. They become spoon-shaped, soft, and brittle. Koilonychia has many causes, but it’s often found in people who are low in iron or have an iron storage condition such as hemochromatosis.

Though koilonychia is not painful or harmful, the underlying condition that is causing it may need to be addressed by a healthcare provider. If you notice indentations in your nails so that they look cupped or concave, see a healthcare provider.

Good nail care, including keeping your nails clean and moisturized, may help, but it’s important to determine what is causing koilonychia.

A Word From Verywell

Spoon nails can mean you may have a medical condition that needs treatment. In many cases, you can get healthy-looking nails back, though you have to be patient. It takes months for your nails to grow out, but you can try to stimulate growth by massaging the cuticles with a good cream.