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Fungal nail infection (onychomycosis)

Onychomycosis is a fungal infection of the nail. It is very common, especially in toenails, and its distinguishing practical feature is the patience it…

This page provides general information and does not replace a doctor’s consultation. If symptoms are severe, persistent or worsening, seek medical advice promptly.

Onychomycosis is a fungal infection of the nail. It is very common, especially in toenails, and its distinguishing practical feature is the patience it demands: the nail grows slowly and treatment is measured in months, not weeks. People who abandon it halfway end up back where they started, and that is the most common reason for "it never clears".

How it presents

  • the nail changes colour: yellowish, whitish, brown or blotchy;
  • it thickens and becomes hard to cut;
  • it crumbles at the free edge;
  • it lifts away from the nail bed, leaving a gap underneath;
  • whitish crumbly material builds up beneath it;
  • it can become deformed and painful in shoes;
  • sometimes there is an unpleasant smell;
  • it almost always starts at the free edge and advances towards the root;
  • in most cases there is athlete's foot on the skin as well.

What makes it more likely

  • untreated athlete's foot — the commonest origin;
  • older age, because the nail grows more slowly;
  • diabetes, circulatory problems, reduced immunity;
  • repeated nail trauma: sport, tight footwear;
  • prolonged moisture: closed footwear, sweating, working with water;
  • shared damp floors: pools, changing rooms, saunas;
  • nail psoriasis, which is also confused with fungal infection;
  • manicure and pedicure with unsterilised instruments;
  • gel nails and long-worn semi-permanent polish.

Why it should be confirmed before treating

This is the key point of the article. Only about half of nails that look "fungal" actually have a fungus. The rest are psoriasis, repeated trauma, lichen planus, circulatory changes or age-related change. Since oral treatment lasts months and requires blood monitoring, it is not started blind: a nail sample is taken for microscopy and culture, or for PCR.

There is also one situation that cannot wait: a dark longitudinal band in a nail, or a colour change in a single nail with no history of injury, must be assessed to exclude nail melanoma.

When to see a doctor

  • a nail has changed colour, thickness or shape;
  • it hurts when walking or in shoes;
  • you have diabetes, neuropathy or circulatory problems — always seek advice rather than self-treating;
  • the surrounding skin is red, swollen, hot or discharging;
  • there is a dark band in the nail or a mark that is enlarging;
  • several nails are affected;
  • over-the-counter treatments have not worked in three months;
  • there are lesions on the elbows, knees or scalp — this may be psoriasis.

Treatment

  • antifungal lacquers and solutions — amorolfine, ciclopirox: useful where less than half the nail is affected and the root is spared. Applied for 6–12 months;
  • oral antifungals — terbinafine, itraconazole: far more effective for extensive involvement. Three to four months for toenails, six to twelve weeks for fingernails. They require liver function monitoring and a check for interactions with other medicines;
  • filing or reducing the nail — thins it and helps the product penetrate;
  • chemical or surgical nail removal in selected cases;
  • laser — results are inferior to oral treatment and the evidence is limited;
  • treat athlete's foot at the same time: without this, reinfection is only a matter of time.

About timescales: a toenail takes 9–12 months to grow out completely. Even if the fungus is dead by the second month of treatment, the damaged part of the nail will still be there until it has grown out entirely. An ugly nail does not mean the treatment has failed.

How to prevent recurrence

  • dry your feet thoroughly, particularly between the toes;
  • breathable socks changed daily;
  • alternate footwear and let each pair dry for 24 hours;
  • disinfect footwear with antifungal powder or spray during and after treatment;
  • flip-flops in showers and changing rooms;
  • cut nails straight across with your own instruments;
  • do not share clippers or files, and ensure salon equipment is sterilised;
  • treat any skin fungal infection as soon as it appears;
  • take breaks between semi-permanent manicures;
  • if you have diabetes, check your feet daily.

Common questions

Is it contagious? Yes, via shared damp floors, towels and manicure equipment, and also within the same household.

Can I paint the nail? During treatment it is better not to: polish hides the progress, and medicated lacquers do not work underneath it.

Do vinegar or tea tree oil work? They do not eradicate the infection. At best they improve the appearance slightly.

Are the tablets dangerous? Terbinafine has been in use for decades; blood monitoring and an interaction check make it safe for most people.

Can I leave it untreated? If it does not bother you, that is a reasonable option to discuss. But the infection advances, spreads to other nails and, in people with diabetes, can lead to complications.

Online consultation

In an online consultation the doctor reviews photographs of the nails, explains why it is worth confirming the fungus with a sample before months of treatment, reviews your medicines for interactions, chooses between lacquer and oral treatment, and sets out realistic timescales for improvement.

This material is for information only and does not replace a medical consultation.

Consult with a doctor about Fungal nail infection (onychomycosis)

Consult with a doctor about Fungal nail infection (onychomycosis)

Discuss your symptoms and possible next steps with a doctor online.

Medically reviewed by

Andrei Popov
Andrei Popov
General medicineMedical License: 464628925

Reviewed on Jul 23, 2026

Online doctors for Fungal nail infection (onychomycosis)

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5.0(1)

Tomasz Grzelewski

DermatologyAllergology21 years of experience

Dr Tomasz Grzelewski is an MD, PhD specialist in allergy, paediatrics, general practice and sports medicine, with a clinical focus on dermatology, endocrinology, allergology and sports-related health. He has more than 20 years of clinical experience and completed his medical training at the Medical University of Łódź, where he defended his PhD thesis with distinction. His doctoral research was recognised by the Polish Society of Allergology for its innovative contribution to the field. Throughout his career, he has gained extensive expertise in diagnosing and managing a wide range of allergic and paediatric conditions, including modern allergen desensitisation techniques. For five years, Dr Grzelewski served as the Head of two paediatric departments in Poland, managing complex clinical cases and leading multidisciplinary teams. He also worked in medical centres in the United Kingdom, gaining experience across both primary care and specialist environments. With over a decade of telemedicine experience, he has provided online consultations across Europe and is valued for his clear, structured and evidence-based medical guidance. Dr Grzelewski is actively involved in clinical programmes focused on modern anti-allergic therapies. As a Principal Investigator, he leads research projects on sublingual and oral allergen desensitisation, supporting evidence-based progress in allergy treatment for both children and adults. In addition to his background in allergology and paediatrics, he completed dermatology studies through the Cambridge Education Group (Royal College of Physicians of Ireland) and a Clinical Endocrinology course at Harvard Medical School. This advanced training enhances his ability to manage skin manifestations of allergies, atopic conditions, urticaria, endocrine-related symptoms and complex immunological reactions. Patients commonly seek his care for: 

  • seasonal and perennial allergies
  • allergic rhinitis and chronic nasal symptoms
  • asthma and breathing difficulties
  • food and medication allergies
  • urticaria, atopic dermatitis and skin reactions
  • recurrent infections in children
  • sports-related health questions
  • general family medicine concerns

Dr Tomasz Grzelewski is known for his clear communication style, structured medical approach and ability to explain treatment options in a concise and accessible way. His multidisciplinary background across allergy, paediatrics, dermatology and endocrinology allows him to provide safe, up-to-date and comprehensive care for patients of all ages.

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€106
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Lizaveta Trafimchuk Takhvaniuk

DermatologyGeneral medicine10 years of experience
Licence no. 58788

Dr. Lizaveta Trafimchuk Takhvaniuk graduated in Medicine and subsequently specialized in Dermatology and Venereology. She has more than 10 years of clinical experience and is licensed to practice in Spain, where she focuses on the comprehensive diagnosis and treatment of dermatological conditions.

Throughout her education and professional career, Dr. Trafimchuk has gained extensive experience in managing diseases of the skin, hair, and nails, as well as in the diagnosis, treatment, and prevention of sexually transmitted infections (STIs). Her clinical approach is based on evidence-based medicine, combined with personalized care tailored to each patient’s needs.

In her daily practice, she treats a wide range of dermatological conditions, including chronic inflammatory dermatoses such as acne, rosacea, atopic dermatitis, psoriasis, and eczema. She also has experience in treating pigmentation disorders, including melasma, post-inflammatory hyperpigmentation, and dyschromia.

She has developed a particular interest in trichology, treating various types of alopecia, chronic hair loss, and scalp disorders. In addition, she has experience in managing infectious dermatoses of fungal, viral, and bacterial origin, as well as in evaluating benign and suspicious skin lesions, with referral to specialized care when necessary.

With a strong interest in a comprehensive approach to skin health, she also treats scars, post-procedural skin changes, and conditions related to hormonal factors and aging, including those associated with pregnancy, menopause, and age-related skin changes.

Thanks to her experience and continuous professional development, Dr. Trafimchuk provides high-quality medical care that is professional, confidential, and aligned with modern dermatology standards.

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€72
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Daria Litash

Dermatology2 years of experience
Licence no. 69233

Dr. Daria Litash is an experienced physician specializing in general medicine, weight management, healthy weight loss, and overall wellness. Her approach combines thorough medical assessment with personalized recommendations to help patients improve their health and maintain an active, balanced lifestyle.

During every online consultation, she places particular emphasis on taking a detailed medical history and identifying the underlying causes of symptoms. When clinically appropriate, she recommends blood tests or additional diagnostic investigations to provide a more accurate assessment and create an individualized treatment plan.

Her main areas of expertise include:

  • Healthy weight management and weight loss
  • Overweight treatment and long-term weight maintenance
  • Hair loss assessment and management
  • Skin health evaluation
  • General medical consultations for adults
  • Preventive medicine and healthy lifestyle guidance

Dr. Litash also holds a qualification in Aesthetic Medicine, allowing her to approach skin and hair concerns from both a medical and preventive perspective, always following evidence-based principles and current clinical recommendations.

Her professional background includes several years of experience working in community pharmacy in Spain, providing her with extensive knowledge of medications, treatment options, and therapeutic alternatives available on the Spanish market, as well as experience in selecting international pharmaceutical products when clinically appropriate.

Her online consultations are designed to provide clear, personalized, and patient-centered medical care, helping individuals better understand their health, make informed treatment decisions, and achieve sustainable long-term wellbeing.

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€96

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