What Is Koilonychia (Spoon Nails)?

Koilonychia, commonly known as spoon nails, is a condition where the fingernails or toenails appear abnormally thin and concave, resembling the shape of a spoon. The edges of the nail are raised, while the center is sunken in. This condition may occur on one or more nails and is sometimes a sign of an underlying health issue.

What Causes Koilonychia?

Koilonychia can develop due to various reasons. Some of the most common causes include:

• Iron-deficiency anemia – the most frequent cause of spoon-shaped nails.
• Hemochromatosis – a condition where the body absorbs too much iron.
• Hypothyroidism – an underactive thyroid gland.
• Raynaud’s disease – a disorder affecting blood circulation.
• Lupus erythematosus – an autoimmune condition.
• Repeated nail trauma – such as from aggressive manicuring or injury.
• Frequent exposure to solvents – especially petroleum-based products.
• Hereditary factors – some people may be born with spoon-shaped nails, particularly infants, where it may correct naturally over time.

What Are the Symptoms of Koilonychia?

The main sign of koilonychia is the appearance of the nails. Symptoms may include:

• Thin, soft nails that can easily break.
• Nails that curve upward at the edges with a sunken center.
• Brittle texture.
• In cases caused by anemia, symptoms like fatigue, weakness, or pale skin may also be present.

How Is Koilonychia Diagnosed?

A healthcare provider usually diagnoses koilonychia based on the appearance of the nails. However, to determine the underlying cause, additional tests may be ordered, such as:

• Complete blood count (CBC) – to check for anemia.
• Iron studies – to assess iron levels in the body.
• Thyroid function tests – to detect hypothyroidism.
• Liver function tests – especially if hemochromatosis is suspected.
• Family medical history – to check for hereditary patterns.

What Is the Treatment for Koilonychia?

Treatment depends on the underlying cause of the condition:

• Iron supplementation – if the spoon nails are due to iron-deficiency anemia.
• Treating chronic conditions – such as thyroid disorders or autoimmune diseases.
• Protecting the nails – from repeated trauma or exposure to harsh chemicals.
• Using moisturizers – to keep the nails healthy and prevent cracking or splitting.

In genetic cases or when it appears in infants, the condition often resolves on its own as the child grows.

When Should You See a Doctor?

You should consult a doctor if:

• Your nails suddenly change shape or texture.
• You experience symptoms like fatigue, pale skin, or dizziness.
• The condition persists or worsens over time.
• Other symptoms suggest a possible underlying disease.

What Is the Outlook for People with Koilonychia?

The outlook depends on the cause. If koilonychia is related to iron deficiency or another treatable condition, the nails can return to normal over time with proper care. Nail changes may take several months to improve as healthy nails grow out. For hereditary or lifelong conditions, the changes in nail shape may persist but can often be managed without complications.