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Medical Dermatology

Nail Disorders

Nails are easy to overlook, but they develop a range of problems — from stubborn fungal infections and painful ingrown toenails to changes that reflect a skin condition, and, rarely, a pigmented streak that should never be ignored.

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At a glance

What it is
A range of nail conditions — fungal infection, ingrown nails, nail changes from skin disease, and pigmented streaks.
Who it affects
Anyone. Fungal nails are especially common in humid climates; ingrown toenails affect many at some point.
Common problems
Thickened or discoloured nails, painful ingrown edges, pitting from psoriasis.
Not to be missed
A new or changing dark streak in a nail should always be assessed.
Treatment
Confirming the diagnosis first, then targeted treatment — oral antifungals, minor nail surgery, or treating the underlying condition.
Understanding the condition

Why nails matter

Nails can be affected by infection, injury and pressure, and they also act as a window onto the skin — several skin conditions show first, or most clearly, in the nails. Because quite different problems can produce similar-looking changes, the useful first step is nearly always to confirm what is actually going on before starting treatment.

This matters especially for fungal nail infection, where treatment is long, and for pigmented streaks, where the stakes of missing something are high.

The one not to ignore A new, widening or irregular dark streak running along a nail should always be assessed. Most are harmless — and they are more common in darker skin — but occasionally such a streak is an early sign of a melanoma of the nail unit, a form of skin cancer that is particularly relevant in Asian skin. Prompt assessment is the safe course.
Recognising the problem

Common nail conditions

Different problems, different treatments — which is why diagnosis comes first.

🧿

Fungal nail infection

Onychomycosis — the commonest cause of an abnormal nail.

  • Thickened, discoloured, crumbly nails
  • Often follows athlete's foot
  • Usually needs oral treatment to clear
🔧

Ingrown toenail

The nail edge growing into the surrounding skin.

  • Pain, redness and swelling at the edge
  • Can become infected
  • Treated with a minor procedure when needed
🟩

Nail psoriasis

Nail changes reflecting a skin condition.

  • Pitting of the nail surface
  • Discolouration and separation from the bed
  • Often alongside skin psoriasis
🔬

Nail trauma

Damage from injury or pressure.

  • Bruising under the nail
  • Thickening from repeated pressure
  • Can mimic other nail conditions
⚫

Pigmented streaks

A dark band running along the nail.

  • Often harmless, especially in darker skin
  • But a new or changing streak needs review
  • Assessed to exclude melanoma of the nail
💉

Other nail changes

Nails reflecting eczema or other conditions.

  • Ridging and irregularity
  • Changes at the nail folds
  • Assessed alongside the skin
Treatment

How nail disorders are treated

Treatment is directed at the diagnosis, which is why confirming it first is worthwhile:

  • Fungal nail infection — usually oral antifungal treatment, since creams cannot penetrate the nail adequately; a nail sample confirms the diagnosis before a long course
  • Ingrown toenail — a minor procedure under local anaesthetic to remove the offending edge, and treatment of the nail matrix where the problem keeps recurring
  • Nail psoriasis and other skin-related changes — treating the underlying skin condition
  • A suspicious pigmented streak — assessment, and a nail-unit biopsy where indicated
Nails grow slowly Even when treatment works, a healthy nail takes months to grow out and replace an abnormal one — up to a year for a big toenail. Confirming the diagnosis before starting avoids a long course of treatment for something that turns out not to be what it seemed.

Minor nail surgery is part of our surgical dermatology service.

Seeking help

When to see a dermatologist

Consider an assessment for:

  • Nails that are thickened, discoloured or crumbly and not improving
  • A painful or recurrent ingrown toenail
  • Nail changes that might reflect a skin condition such as psoriasis
  • Any new, changing or irregular dark streak in a nail — this should always be checked promptly
  • Nail problems in someone with diabetes, where foot care needs particular attention

Confirming the diagnosis is especially useful before starting the long treatment course that fungal nail infection requires.

Dr Chen Qiping, Consultant Dermatologist, Chen Dermatology Singapore

Dr Chen Qiping

Consultant Dermatologist · MBBS, MRCP (UK), M.Sc, FAMS (Dermatology)

Dr Chen practises general and surgical dermatology, including nail disorders and minor nail surgery, alongside laser and cosmetic dermatology. Consultations are available in English and Mandarin.

Full profile →
Common questions

Nail disorders — frequently asked questions

What causes thickened, discoloured toenails?
The most common cause of thickened, discoloured or crumbly nails is a fungal nail infection (onychomycosis), which often follows athlete's foot. However, several other conditions can look similar — psoriasis, trauma to the nail, and less commonly other nail diseases. Because the appearance overlaps, and because fungal nail infection usually needs oral treatment to clear, confirming the diagnosis (often with a nail sample) is worthwhile before committing to a long treatment course.
Is an ingrown toenail something a dermatologist treats?
Yes. An ingrown toenail — where the edge of the nail grows into the surrounding skin, causing pain, redness and sometimes infection — can be treated with a minor procedure under local anaesthetic. This may involve removing the offending edge of the nail and, where the problem is recurrent, treating the nail matrix so that the edge does not regrow. It is a common and very treatable problem.
Can changes in my nails be a sign of a skin condition?
Yes. Several skin conditions show in the nails. Psoriasis commonly causes pitting, discolouration and separation of the nail from its bed; eczema can affect the nail folds; and alopecia areata can produce fine pitting. Because the nails can reflect what is happening in the skin, nail changes are sometimes the clue that leads to a diagnosis, which is one reason they are worth examining properly.
Should I be worried about a dark streak in my nail?
A new, widening or irregular pigmented streak running along a nail should always be assessed rather than ignored. While many pigmented streaks are harmless — and they are more common in people with darker skin — a dark band in the nail can occasionally be an early sign of a melanoma of the nail unit, which is one of the forms of skin cancer that is more relevant in Asian skin. Prompt assessment is the safe course.
Why does fungal nail infection take so long to treat?
Nails grow slowly, so even when treatment is working, it takes months for a healthy nail to grow out and replace the infected one — often up to a year for a big toenail. Creams struggle to penetrate the nail, which is why oral antifungal treatment is usually needed. Patience and completing the full course are important, and confirming the diagnosis first avoids a long course of treatment for something that turns out not to be fungal.
When should I see a dermatologist about my nails?
Consider assessment for nails that are thickened, discoloured or crumbly and not improving; a painful or recurrent ingrown toenail; nail changes that might reflect a skin condition such as psoriasis; and — importantly — any new, changing or irregular dark streak in a nail, which should always be checked promptly. Confirming the diagnosis is particularly useful before starting long-term treatment.

References

  1. DermNet. Nail disorders, Onychomycosis and Ingrown toenail. dermnetnz.org
  2. American Academy of Dermatology. Nail conditions. aad.org
  3. DermNet. Melanoma of nail unit. dermnetnz.org

Page last reviewed: 28 July 2026.

Important — This page is general information about a skin condition and is not medical advice. It cannot take the place of an individual consultation, examination and diagnosis. Treatment options, their suitability and their possible side effects should be discussed with a qualified doctor who has assessed your skin. Individual results vary. If you have concerns about your skin, please arrange a consultation.

Concerned about a nail problem?

Arrange a consultation with Dr Chen Qiping at our Collyer Quay clinic — two minutes' walk from Raffles Place MRT. Consultations available in English and Mandarin.

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