What is the evaluation for toenail discoloration, also known as onychodystrophy or chromonychia (change in nail color)?

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From the Guidelines

Toenail discoloration should be evaluated by a healthcare provider to determine the underlying cause, which could include fungal infection, trauma, psoriasis, or systemic conditions. For fungal infections, which are the most common cause, treatment typically involves topical antifungal medications like ciclopirox 8% nail lacquer applied daily for up to 48 weeks, or oral medications such as terbinafine 250 mg daily for 12 weeks or itraconazole 200 mg twice daily for one week per month for three months 1. Traumatic discoloration usually resolves as the nail grows out, while discoloration from psoriasis may require corticosteroids or other treatments for the underlying condition. Prevention includes keeping feet clean and dry, wearing breathable footwear, avoiding walking barefoot in public areas, and trimming nails straight across 1. Some noninfectious conditions can produce nail changes that mimic onychomycosis, but the nail surface does not usually become soft and friable as in a fungal infection, and these include chronic trauma, psoriasis, onycholysis, onychogryphosis, subungual malignant melanoma and lichen planus 1. Persistent or worsening discoloration, especially with pain or changes in nail texture, warrants prompt medical attention as it could indicate a more serious condition like melanoma. Treatment success depends on accurate diagnosis and consistent application of prescribed therapies, with improvement often taking months as healthy nail grows in 1. It is essential to note that onychomycosis can have a significant impact on the quality of life of patients, including discomfort, difficulty in wearing footwear and walking, cosmetic embarrassment and lowered self-esteem, and can also lead to the development of foot ulcers, osteomyelitis, cellulitis and gangrene in diabetic patients 1. Therefore, evaluation and treatment of toenail discoloration should prioritize the patient's quality of life and morbidity, and healthcare providers should raise attention and provide proper care to patients with nail diseases. Some key points to consider in the evaluation and treatment of toenail discoloration include:

  • Accurate diagnosis of the underlying cause of toenail discoloration
  • Consistent application of prescribed therapies
  • Prevention of fungal infections through keeping feet clean and dry, wearing breathable footwear, and avoiding walking barefoot in public areas
  • Consideration of the patient's quality of life and morbidity in the evaluation and treatment of toenail discoloration
  • Prompt medical attention for persistent or worsening discoloration, especially with pain or changes in nail texture.

From the FDA Drug Label

The incidence of nail disorders was similar between the treatment groups (2% [6/327] in the Ciclopirox Topical Solution, 8%, (Nail Lacquer), group and 2% [7/328] in the vehicle group) Moreover, application site reactions and/or burning of the skin occurred in 1% of patients treated with Ciclopirox Topical Solution, 8%, (Nail Lacquer), (3/327) and vehicle (4/328). Other TEAEs thought to be causally related included nail disorders such as shape change, irritation, ingrown toenail, and discoloration.

The toenail discoloration is a possible adverse event associated with the use of Ciclopirox Topical Solution, 8%, (Nail Lacquer), as reported in the clinical trials 2.

  • The incidence of nail disorders, including discoloration, was similar between the treatment groups.
  • Nail disorders such as shape change, irritation, ingrown toenail, and discoloration were reported as treatment-emergent adverse events. It is essential to monitor patients for any signs of nail disorders, including discoloration, during treatment with Ciclopirox Topical Solution, 8%, (Nail Lacquer).

From the Research

Toenail Discoloration Evaluation

Toenail discoloration can be a symptom of various underlying conditions, including fungal infections, systemic diseases, or trauma. The evaluation of toenail discoloration involves a detailed history and clinical examination of all 20 nail units, as well as diagnostic tests such as dermoscopy, diagnostic imaging, and histopathologic and mycological analyses 3.

Causes of Toenail Discoloration

Some common causes of toenail discoloration include:

  • Fungal infections, such as onychomycosis, which can cause nail discoloration, thickening, and onycholysis 4, 5, 6, 7
  • Systemic diseases, such as diabetes or liver disease, which can cause nail changes, including discoloration 3
  • Trauma or injury to the nail, which can cause discoloration or other nail changes 3

Diagnostic Approaches

Diagnostic approaches for toenail discoloration may include:

  • Clinical examination of the nail and surrounding tissue 3
  • Dermoscopy, which can help to visualize the nail and surrounding tissue in greater detail 3
  • Diagnostic imaging, such as X-rays or ultrasound, which can help to evaluate the underlying structure of the nail and surrounding tissue 3
  • Histopathologic and mycological analyses, which can help to diagnose fungal infections or other conditions affecting the nail 3, 4, 5, 6, 7

Treatment Options

Treatment options for toenail discoloration depend on the underlying cause and may include:

  • Topical or oral antifungal medications for fungal infections 4, 5, 6, 7
  • Treatment of underlying systemic diseases or conditions 3
  • Surgical or other interventions for traumatic or other causes of nail discoloration 3
  • Patient education on proper nail care and techniques to minimize further damage to the affected nails 3

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Fungal nail infections: diagnosis and management.

Prescrire international, 2009

Research

Efinaconazole in Onychomycosis.

American journal of clinical dermatology, 2022

Research

Topical and device-based treatments for fungal infections of the toenails.

The Cochrane database of systematic reviews, 2020

Research

Fungal toenail infections.

BMJ clinical evidence, 2014

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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