Nail and Skin Conditions of the Feet: What to Look For and When to See a Podiatrist

The skin and nails of the feet are often overlooked until something becomes painful, uncomfortable or difficult to manage. Yet changes in the toenails or skin can sometimes provide important clues about infection, pressure, circulation, general health and the way the feet are functioning.

Common problems such as fungal infections, corns, calluses and ingrown toenails are usually manageable, but persistent or unusual changes should not simply be ignored. A discoloured toenail is not always fungal, a thickened area of skin is not always "just a callus", and a dark mark beneath a nail should not automatically be assumed to be bruising.

Understanding what to look for can help you know when simple foot care may be sufficient and when professional assessment is appropriate.

Healthy Skin and Nails

Healthy foot skin should generally be intact, comfortable and free from persistent cracks, sores, scaling or areas of unexplained discolouration.

Healthy toenails are usually:

• firmly attached to the nail bed;

• relatively smooth;

• reasonably uniform in colour;

• not excessively thick;

• free from persistent pain or swelling around their edges.

Some variation is perfectly normal. Nails may become slightly thicker or more ridged with age, and the appearance of the skin differs considerably between individuals.

What matters most is noticing new, persistent or progressive changes.

Common Toenail Conditions

Fungal Nail Infection

A fungal nail infection, medically known as onychomycosis, is one of the most common nail problems affecting the feet.

Fungi tend to thrive in warm, damp environments, making the feet particularly susceptible when moisture becomes trapped inside footwear. Athlete's foot can also spread from the surrounding skin into the nails.

A fungal toenail may become:

• yellow, brown, white or otherwise discoloured;

• thicker than normal;

• brittle or crumbly;

• distorted in shape;

• difficult to cut;

• partially separated from the skin beneath it;

• surrounded by debris underneath the nail.

Fungal nail infection often progresses slowly and may initially affect only one corner of a nail.

Warm, moist environments encourage the fungi responsible for athlete's foot and fungal nail infections, so keeping the feet clean and dry and regularly changing socks and footwear can help reduce risk. CDC

Not Every Thick or Yellow Nail Is Fungal

This is important.

Toenails can change appearance because of:

• repeated pressure from shoes;

• previous injury;

• psoriasis;

• ageing;

• poor nail growth;

• certain medical conditions; or

• other nail disorders.

For this reason, antifungal treatment may fail when the original problem was never fungal.

Where there is doubt, a nail sample can sometimes be taken for laboratory testing before prolonged treatment is started. nhs.uk

Treating Fungal Nails

Treatment depends on how much of the nail is affected and how troublesome the condition is.

Options may include:

• regular thinning and reduction of thickened nail;

• topical antifungal preparations;

• antifungal medication prescribed by a doctor;

• treatment of associated athlete's foot;

• footwear and hygiene measures.

Toenails grow slowly, so even successful treatment does not produce a normal-looking nail immediately. It may take many months for healthier nail to grow from the base towards the tip.

Athlete's Foot

Athlete's foot, or tinea pedis, is a fungal infection of the skin.

Despite the name, you do not need to be an athlete to develop it.

It commonly affects the spaces between the toes but can also involve the soles and sides of the feet.

Symptoms may include:

• itching;

• peeling or flaking skin;

• white, softened skin between the toes;

• burning or irritation;

• cracking;

• small blisters;

• dry or scaly areas.

On darker skin, fungal infections do not always appear bright red. Areas may look brown, grey, purple or darker than the surrounding skin, depending on the individual's skin tone. CDC

Why Athlete's Foot Matters

Athlete's foot may appear minor, but cracks in the skin can provide an entry point for bacteria.

The infection can also spread to the toenails, making treatment considerably more difficult.

Reducing Your Risk

Helpful measures include:

• drying carefully between the toes;

• changing damp socks;

• allowing shoes to dry properly;

• alternating footwear where possible;

• avoiding sharing towels and nail instruments;

• wearing footwear in communal changing areas and showers.

These measures are particularly relevant in hot climates where the feet may remain warm and moist for extended periods. CDC

Ingrown Toenails

An ingrown toenail develops when the edge of the nail irritates or penetrates the skin alongside it.

The big toe is most commonly affected.

Symptoms may begin with:

• tenderness at the side of the nail;

• redness or swelling;

• pain when wearing shoes;

• discomfort when pressure is applied.

If the skin is broken, the area may subsequently become infected.

Possible contributing factors include:

• cutting the nails too short;

• rounding deeply into the corners;

• tight or narrow footwear;

• naturally curved nails;

• trauma;

• repeated sporting pressure.

Should You Dig Out an Ingrown Nail?

Repeatedly cutting deeply into the corner of the nail often provides temporary relief but can make the problem worse as the nail grows back.

People with diabetes, poor circulation or reduced sensation should be particularly cautious about attempting home treatment.

A podiatrist can remove the offending nail edge safely and, where the problem repeatedly returns, discuss procedures designed to permanently prevent that particular edge of nail from growing back.

Thickened Toenails

Toenails may gradually become thicker because of:

• fungal infection;

• repeated shoe pressure;

• trauma;

• ageing;

• psoriasis;

• altered nail growth.

Very thick nails can become painful inside footwear and may be extremely difficult for an individual to cut safely.

Podiatric treatment can involve carefully reducing the thickness and length of the nail, making it more comfortable and easier to manage.

Traumatised and Bruised Toenails

Running, football, hiking, tight shoes or dropping something onto a toe can cause bleeding beneath the nail.

This may produce a dark purple, brown or black area known as a subungual haematoma.

A history of obvious trauma often makes the cause relatively clear.

As the nail grows, the discolouration should gradually move towards the end of the toe.

However, a dark mark underneath a nail that has no obvious explanation, is changing, widening or does not grow out with the nail deserves professional assessment.

Dark Lines or Pigmentation in Toenails

People with darker skin can naturally have pigmented bands within their nails. Many are completely benign.

Nevertheless, new or changing pigmentation should not automatically be dismissed.

Melanoma can occasionally develop underneath or around a toenail and may initially appear as a brown or black vertical band. Warning signs can include a new or changing dark streak, widening pigmentation or pigment extending onto the skin surrounding the nail. American Academy of Dermatology

This is especially important in people with darker skin tones because melanoma may occur on the soles, toes and around or beneath the nails—areas that may receive very little sun exposure. American Academy of Dermatology

Most dark toenails are not melanoma, but unexplained changes should be examined rather than guessed at.

Nail Psoriasis

Psoriasis can affect toenails as well as the skin.

Nail changes may include:

• small pits in the nail surface;

• thickening;

• yellow-brown discolouration;

• separation of the nail from the nail bed;

• debris underneath the nail;

• crumbling.

Because nail psoriasis can resemble fungal infection, accurate diagnosis is important.

Some patients may have both conditions at the same time.

Common Skin Conditions of the Feet

Corns

A corn is a small, concentrated area of thickened skin that develops in response to repeated pressure or friction.

Corns often form:

• over prominent toe joints;

• between the toes;

• on the tips of toes;

• underneath areas of increased pressure.

A corn has a central area of hardened skin that can press into the underlying tissues, making it feel as though a small stone is embedded in the foot.

Corns are not roots growing into the foot.

Removing the hard skin may provide relief, but if the source of pressure remains, the corn is likely to return.

A podiatrist will therefore consider why the corn developed, including:

• footwear;

• toe deformity;

• walking mechanics;

• abnormal pressure;

• bony prominence.

Calluses

A callus is a broader area of thickened skin.

Callus is the body's protective response to repeated friction and pressure.

It commonly develops:

• underneath the ball of the foot;

• along the heel;

• around prominent joints;

• on the toes.

A small amount of callus may cause no problem at all.

However, excessive callus can become painful and occasionally conceal tissue damage beneath it.

This is particularly important in someone with diabetes or reduced sensation.

Should Callus Be Cut at Home?

Using razor blades, knives or other sharp objects to remove callus is risky.

Chemical corn removers containing acids can also damage healthy skin and may be especially hazardous for people with diabetes, poor circulation or neuropathy.

Professional reduction is considerably safer where callus is thick or painful.

Cracked Heels

Dry skin around the heel can become thickened and eventually split, producing heel fissures.

Minor cracks may simply be uncomfortable, while deeper fissures can become painful, bleed or provide an entry point for infection.

Contributing factors include:

• dry skin;

• prolonged standing;

• thick heel callus;

• open-backed footwear;

• excess pressure;

• certain skin disorders.

Treatment may include reducing surrounding callus and using an appropriate moisturising cream.

Products containing ingredients such as urea are commonly used to soften dry, thickened skin.

Cream should generally not be applied heavily between the toes, where excess moisture may encourage fungal infection.

Verrucae and Plantar Warts

A verruca is a wart occurring on the foot. It is caused by certain types of human papillomavirus, or HPV.

Verrucae can occur individually or in clusters.

They may appear as:

• rough areas of skin;

• small circular lesions;

• areas containing tiny dark dots;

• painful areas underneath weight-bearing parts of the foot.

Because standing pushes a plantar wart inward, it may look flatter than a wart elsewhere on the body.

Verruca or Corn?

The two can sometimes look similar.

A podiatrist can often distinguish them by examining:

• the pattern of skin lines;

• the distribution of hard skin;

• small blood vessels within the lesion;

• the way the lesion responds to pressure.

Many verrucae eventually resolve through the body's immune response, but persistent or painful lesions may require treatment.

Blisters

Blisters are usually caused by friction.

They commonly develop after:

• wearing new footwear;

• unusually long periods of walking;

• running;

• poorly fitting shoes;

• excessive moisture.

The outer layer of skin separates and fluid collects underneath.

Small uncomplicated blisters can often be protected and allowed to heal naturally.

However, seek professional advice if a blister:

• appears infected;

• becomes increasingly red or painful;

• contains pus;

• is very large;

• repeatedly occurs in the same place; or

• develops in someone with diabetes or significantly impaired circulation.

Eczema and Dermatitis

Eczema and contact dermatitis can affect the feet.

Possible symptoms include:

• itching;

• scaling;

• dry skin;

• redness or changes in pigmentation;

• small blisters;

• cracking.

Triggers may include materials found in:

• footwear;

• adhesives;

• rubber;

• dyes;

• socks;

• topical products.

Fungal infection and dermatitis can sometimes resemble each other, and using the wrong treatment may prolong the problem.

Persistent rashes therefore deserve proper assessment.

Sweaty Feet

Excessive sweating of the feet is known as plantar hyperhidrosis.

It can contribute to:

• unpleasant odour;

• skin softening;

• increased friction;

• blistering;

• athlete's foot;

• deterioration of footwear.

Helpful measures may include breathable footwear, regular sock changes and suitable antiperspirant products.

Severe cases can sometimes be treated medically.

Foot Odor

Sweat itself is usually not strongly odorous.

Odor develops when sweat interacts with microorganisms on the skin and inside footwear.

Regular washing, drying, changing socks and allowing footwear to dry completely can make a considerable difference.

Persistent strong odor accompanied by small pits or crater-like areas on the soles may indicate a bacterial condition such as pitted keratolysis, which can require treatment.

Bacterial Skin Infection

Broken skin can allow bacteria to enter.

Possible warning signs include:

• increasing redness or darkening around the affected area;

• warmth;

• swelling;

• increasing tenderness;

• pus or discharge;

• spreading inflammation;

• fever or feeling unwell.

These symptoms should not be treated simply as athlete's foot or "a sore".

A spreading bacterial infection such as cellulitis requires medical treatment.

Foot Ulcers

An ulcer is a break in the skin that fails to heal normally.

Ulcers can develop because of:

• diabetes;

• reduced sensation;

• poor circulation;

• repeated pressure;

• trauma;

• deformity.

A foot ulcer can appear deceptively small at the surface while extending more deeply underneath.

This is why ulcers require professional assessment.

Diabetes and Nail or Skin Problems

People living with diabetes need to pay particular attention to changes in their feet.

Diabetes can sometimes be associated with:

• reduced sensation;

• impaired circulation;

• slower healing;

• increased risk of infection.

This means that something relatively minor—a blister, cut, ingrown nail or area of hard skin—can occasionally progress before the person realises there is a problem.

People with diabetes should regularly inspect:

• the tops and soles of the feet;

• between the toes;

• around the nails;

• areas where footwear rubs.

Seek professional advice for unexplained wounds, swelling, colour changes, discharge or persistent skin breakdown.

Skin Cancer Can Occur on the Feet

Skin cancer is not limited to areas that receive obvious sun exposure.

Melanoma and other skin cancers can occur:

• on the soles of the feet;

• between the toes;

• around the nails;

• underneath toenails.

In people with darker skin, cancers occurring on the soles and around the nails can be particularly important because people may assume their skin tone protects them completely from skin cancer. American Academy of Dermatology

The ABCDE Warning Signs

When looking at a pigmented skin lesion, remember:

A – Asymmetry: one half looks different from the other.

B – Border: irregular or poorly defined edges.

C – Colour: several colours or uneven pigmentation.

D – Diameter: many melanomas are greater than approximately 6 mm when diagnosed, although they can be smaller.

E – Evolving: the lesion is changing in size, shape, colour or appearance.

Any spot that repeatedly bleeds, fails to heal, looks different from others or continues changing should be assessed. American Academy of Dermatology

Simple Ways to Keep the Skin and Nails Healthy

Good foot care does not need to be complicated.

• Wash the feet regularly and dry carefully, particularly between the toes.

• Change socks regularly.

• Allow shoes to dry between uses.

• Wear footwear that fits correctly.

• Cut toenails across rather than digging deeply down the sides.

• Avoid sharing nail clippers or files.

• Do not use razors to cut corns or callus.

• Moisturise dry skin, particularly around the heels.

• Check the soles and between the toes regularly.

• Treat athlete's foot promptly.

• Wear suitable footwear in communal shower and pool areas.

• Do not ignore unexplained nail or skin changes.

Good foot hygiene and keeping the feet dry are recognised measures for reducing fungal infections of both the skin and nails. CDC

When Should You See a Podiatrist?

Consider seeing a podiatrist if you have:

• painful or recurring corns or calluses;

• a painful or ingrown toenail;

• very thick nails that are difficult to cut;

• suspected fungal nail infection;

• persistent athlete's foot;

• painful cracked heels;

• repeated blisters;

• a painful verruca;

• unexplained changes in nail shape or colour;

• persistent skin changes;

• difficulty looking after your own feet;

• diabetes or another condition that increases the risk of foot complications.

A podiatrist can assess not only the skin or nail itself but also the pressure, footwear, foot shape, circulation and mechanical factors that may be contributing to the problem.

When Should You Seek Prompt Medical Attention?

Seek timely professional assessment if you notice:

• rapidly spreading redness, swelling or warmth;

• pus or discharge;

• fever associated with a foot problem;

• a wound that is not healing;

• black, blue or unusually pale areas of skin;

• sudden significant swelling;

• severe pain without an obvious explanation;

• a new or changing dark lesion;

• unexplained pigmentation underneath a nail;

• bleeding from a lesion that repeatedly returns;

• infection in someone with diabetes or poor circulation.

People sometimes delay because a foot problem appears small.

With certain conditions, however, the size of a skin lesion does not necessarily indicate its seriousness.

The Bottom Line

Many nail and skin conditions of the feet are common and treatable.

Fungal infections, corns, calluses, cracked heels and ingrown nails account for a large proportion of everyday foot problems. Good hygiene, correctly fitting footwear and regular attention to the skin and nails can prevent many of these conditions from becoming troublesome.

However, appearance alone does not always reveal the cause.

A thickened toenail is not necessarily fungal. A painful area of hard skin may be caused by abnormal pressure. A persistent rash may not simply be athlete's foot. And an unexplained dark mark on the foot or underneath a toenail should never automatically be dismissed as harmless.

Know what is normal for your feet and pay attention when something changes.

When a nail or skin problem is painful, persistent, recurrent or simply does not look right, assessment by a podiatrist or other appropriate healthcare professional can help identify the cause and determine the most suitable treatment.

This information is intended for public education and does not replace individual medical or podiatric assessment.