What is most commonly associated with koilonychia (spoon-shaped nails)?

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From the Guidelines

Iron deficiency anemia is most commonly associated with koilonychia, or spoon-shaped nails. This condition presents as thin nails with a concave depression in the center, giving them a spoon-like appearance. When iron levels in the body are depleted, nail formation is affected, leading to this characteristic change in nail structure, as noted in the British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults 1. According to these guidelines, iron deficiency can lead to various symptoms, including angular stomatitis, glossitis, koilonychia, restless legs syndrome, pagophagia, and blue sclerae.

Key points to consider in the diagnosis and management of koilonychia include:

  • Investigating iron deficiency anemia as the primary cause
  • Looking for a personal or family background of GI disease that may provide a clue as to the cause of IDA, as suggested by the guidelines 1
  • Considering treatment with oral iron supplements to address the underlying iron deficiency
  • Being aware of potential gastrointestinal side effects of iron supplements, such as constipation or dark stools

It's essential to prioritize iron deficiency anemia as the most common cause of koilonychia, given the strong association supported by recent clinical guidelines 1. Other less common causes, such as hemochromatosis, Raynaud's disease, trauma, and certain occupational exposures, should also be considered but are less likely to be the primary cause.

From the Research

Koilonychia Association

  • Koilonychia, also known as spoon-shaped nails, is most commonly associated with iron deficiency 2, 3, 4, 5.
  • Iron deficiency can be caused by various factors such as malnutrition, chronic blood loss, or malabsorption 2.
  • Koilonychia can also be idiopathic or related to occupation and rare systemic disorders 2.
  • Other possible causes of koilonychia include psoriasis, fungus, or trauma 6.
  • The presence of koilonychia should prompt investigations for iron deficiency 2.

Systemic Diseases

  • Koilonychia may be a clue to underlying systemic diseases such as anemia, hemochromatosis, or connective tissue disorders 3, 5.
  • It is essential to conduct a thorough but reasonable search for a primary etiology when koilonychia is present 6.
  • In some cases, koilonychia may be completely idiopathic and of no consequence to the patient 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Spoon nails: still seen in today's world.

Clinical case reports, 2018

Research

Nail abnormalities: clues to systemic disease.

American family physician, 2004

Research

Clubbing and koilonychia.

Dermatologic clinics, 1985

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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