Why do chemotherapy patients experience nail discoloration, including blackening of the nails?

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Last updated: June 22, 2025View editorial policy

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From the Guidelines

Chemotherapy patients experience nail discoloration, including blackening, due to the damaging effects of certain chemotherapy drugs on the cells that produce nails, primarily taxanes, platinum compounds, anthracyclines, and cyclophosphamide. This occurs because these medications affect rapidly dividing cells throughout the body, including the nail matrix where new nail cells are produced, as seen in treatments such as CAF chemotherapy 1 and Docetaxel/capecitabine chemotherapy 1. The damage can manifest as melanonychia (black or brown lines), complete nail darkening, or Beau's lines (horizontal grooves), and is a result of disrupted melanocyte function, causing abnormal pigment production, or damage to blood vessels under the nail, leading to bleeding and subsequent darkening. Some key points to consider include:

  • The discoloration typically begins several weeks after starting treatment and may persist for months after completion.
  • Patients should monitor for signs of infection like increased pain, swelling, or discharge around the nails.
  • Keeping nails short, clean, and moisturized can help manage symptoms.
  • The discoloration usually resolves as new, healthy nail grows out after treatment ends, with treatments such as CMF chemotherapy 1 and GT chemotherapy 1 also being associated with nail changes. It's essential for patients to be aware of these potential side effects and take preventive measures to minimize their impact on quality of life.

From the Research

Nail Discoloration in Chemotherapy Patients

  • Chemotherapy patients often experience nail discoloration, including blackening of the nails, due to the toxic effects of chemotherapeutic agents on the nail matrix and nail bed 2, 3.
  • The most common nail changes induced by chemotherapeutic agents include diffuse hyperpigmentation, longitudinal melanonychia, Beau's lines, onychomadesis, and Mees' lines 2.
  • A study of 205 patients undergoing chemotherapy found that 60.4% of patients developed nail changes, with diffuse hyperpigmentation being the most common change (81.4% of patients) 2.
  • Certain chemotherapeutic agents, such as cyclophosphamide, doxorubicin, and 5-fluorouracil, have been implicated in the development of nail discoloration, including blackening of the nails 2, 3.

Mechanism of Nail Discoloration

  • The exact mechanism of nail discoloration in chemotherapy patients is not fully understood, but it is thought to be related to the toxic effects of chemotherapeutic agents on the nail matrix and nail bed 4, 5.
  • Chemotherapeutic agents can cause damage to the nail matrix, leading to changes in nail pigmentation and texture 4, 5.
  • The synergistic effect of multiple chemotherapeutic agents may also contribute to the development of nail discoloration 3.

Prevention and Management

  • Applying a colorless nail polish or base coat may help prevent nail discoloration and provide photoprotection for the nails 6.
  • Certain colorless nail polishes have been shown to provide significant levels of photoprotection, with SPF values of above 150 6.
  • Early recognition and management of nail changes are important to reduce anxiety and prevent unnecessary investigations in chemotherapy patients 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Nail Changes Induced by Chemotherapeutic Agents.

Indian journal of dermatology, 2020

Research

Chemotherapy-related striate melanonychia: a case report.

Journal of medical case reports, 2021

Research

Nail Changes With Chemotherapeutic Agents and Targeted Therapies.

Indian dermatology online journal, 2022

Research

Drug-induced nail abnormalities.

Expert opinion on drug safety, 2004

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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