What causes thickened toenails?

Thickened toenails can result from multiple causes, sometimes acting together. Determining the source is essential for effective treatment and prevention of recurrence.

• Hereditary factors: Some individuals inherit a natural tendency for thicker nails. If one or both parents have thickened nails, the condition may be passed down genetically.
• Acute trauma: A single injury, such as stubbing your toe or dropping a heavy object on it, can damage the nail bed or matrix, leading to thickened nail growth during healing.
• Chronic trauma: Repeated pressure or friction on the toes—common among runners, dancers, and athletes—can cause long-term nail thickening. Tight or ill-fitting shoes can also create constant pressure, resulting in abnormal nail growth.
• Fungal infection (onychomycosis): One of the most frequent causes of nail thickening, fungal infections weaken the nail plate, causing it to become yellow, brittle, and crumbly as the fungus spreads beneath the nail.
• Ageing: Reduced circulation and slower cell turnover that occur naturally with age make nails thicker, more rigid, and slower to grow.
• Psoriasis: This chronic skin condition can also affect the nails, leading to thickening, pitting, discolouration, and brittleness—a condition known as nail psoriasis.
• Hormonal disorders: Rare hormonal imbalances such as acromegaly (excess growth hormone) can cause abnormally thick or dense nail growth.
• Reduced circulation: Poor blood flow, as seen in diabetes or peripheral vascular disease, disrupts normal nail growth and increases vulnerability to damage and infection.
• Diabetes: Individuals with diabetes often experience thickened toenails due to impaired circulation and a higher likelihood of fungal infection.
• Genetic skin disorders: Conditions such as Darier disease and pityriasis rubra pilaris can lead to nail abnormalities including thickening, ridging, and discolouration.
• Infection or inflammation: Chronic bacterial or yeast infections in or around the nail can trigger thickening, discolouration, and sometimes an unpleasant odour.

In most cases, thickened toenails result from a combination of pressure, infection and reduced nail regeneration. A podiatrist can diagnose the cause and suggest appropriate treatment, from nail debridement, use of protective footwear or antifungal therapy.

What do thickened toenails look like?

Thickened toenails can vary in appearance depending on the cause, but often share similar features:

• Yellow or brown discolouration — common with fungal infections or repeated trauma.
• Increased nail density — visibly thicker and harder than normal, sometimes curving upward or downward.
• Rough or ridged surface — the nail may appear uneven or flaky.
• Brittle, crumbly edges — thick nails may break easily or catch on socks and shoes.
• Separation from the nail bed (onycholysis) — severe thickening may cause lifting or detachment.
• Pain or pressure in footwear — discomfort may occur as the thick nail presses against the shoe or surrounding skin.
• Chalky debris or odour — when infection is present, powdery material may accumulate under the nail.

These changes often develop slowly. If the nail continues to thicken, becomes painful, or is difficult to cut, it should be assessed by a podiatrist.

What are the complications of thickened toenails?

Untreated thickened toenails can cause persistent discomfort and secondary problems:

• Difficulty trimming or wearing shoes due to increased pressure.
• Ingrown toenails or calluses from chronic friction.
• Nail cracking or detachment (onycholysis), creating entry points for infection.
• Secondary fungal or bacterial infections that may spread to other nails or skin.
• Slow healing or ulceration in people with diabetes or poor circulation.
• Permanent nail deformity, discolouration or loss in chronic cases.

How are thickened toenails diagnosed?

Diagnosis begins with identifying the cause behind the nail’s structural change.

• Clinical examination — the podiatrist assesses nail thickness, colour and surrounding skin for signs of infection or trauma.
• Medical history — questions about footwear, activity level, injuries and chronic health conditions help identify contributing factors.
• Laboratory testing — the podiatrist may refer patients to do nail sample testing (e.g. microscopy or culture) to identify the presence of fungi. 

Accurate diagnosis ensures that treatment addresses the root cause rather than just the appearance.

What are the treatment options for thickened toenails in Singapore?

Treatment depends on the underlying cause and the severity of nail thickening. Common approaches include:

• Nail trimming and debridement: A podiatrist carefully thins and smooths thickened nails to reduce pressure and improve comfort.
• Topical antifungal medication: Medicated creams or nail lacquers are advised if a fungal infection is confirmed.
• Lunula Laser (cold laser therapy): This non-invasive, pain-free treatment uses dual-wavelength low-level laser light to promote healing, improve nail health, and assist the body in eliminating pathogens (e.g. fungus). It is safe, chemical-free, and helps reduce the risk of recurrence.
• Partial or total nail removal: In severe or recurring cases, the affected nail may be removed to allow a healthy nail to regrow.
• Protective footwear: Shoes with a wide toe box and breathable materials prevent further trauma or moisture build-up.
• Managing underlying conditions: Controlling diabetes, psoriasis, or circulatory issues supports long-term nail recovery.

Your podiatrist will recommend a tailored plan based on the cause, nail condition, and your overall foot health.

Prevention tips for thickened toenails

Adopting healthy foot habits can prevent toenail thickening and recurrence after treatment:

• Keep feet clean and dry to limit fungal or bacterial growth.
• Wear properly fitted shoes with sufficient toe room and ventilation.
• Keep nails neatly trimmed at all times.
• Change socks daily and use moisture-wicking fabrics.
• Avoid walking barefoot in public areas like pools and gyms.
• Treat early signs of athlete’s foot or nail infection promptly.
• Protect your toes with suitable footwear during sports or heavy work.
• Manage chronic health conditions to maintain good circulation and nail health.

Consistent nail care helps keep toenails strong, comfortable, and free from thickening.

Summary

Thickened toenails (onychauxis) occur when the nail plate becomes abnormally dense, raised, or discoloured—often due to trauma, fungal infection, ageing, or underlying medical conditions. Affected nails may appear yellow or brown, become hard to trim, and cause discomfort or pain when wearing shoes. While sometimes viewed as a cosmetic issue, thickened nails can signal deeper medical concerns that require professional care.

Diagnosis typically involves a clinical examination, review of medical history, and, when necessary, laboratory testing to identify infections or systemic causes. Treatment options may include antifungal medication, professional debridement, or partial nail removal in severe cases. Preventive care—such as wearing proper footwear, maintaining good foot hygiene, and managing systemic conditions—is essential to reduce recurrence.

If you are experiencing painful, discoloured, or hard-to-trim toenails, schedule a consultation with Atlas Podiatry for an accurate diagnosis and personalised treatment plan to restore nail health and relieve discomfort.