Nail Fungus (Onychomycosis): Why It Is Slow to Treat

Nail fungus, called onychomycosis, is a fungal infection that makes nails thick, yellow or brown, brittle and lifted from the skin underneath, and it is slow to treat because nails grow slowly and the infection lives deep under the nail plate. Treatment usually takes many months, and because many other nail conditions look the same, your dermatologist will usually confirm it with a simple nail test before starting.

In India, nail fungus is very common, especially in people who wear closed shoes for long hours, work in wet conditions, have diabetes, or already have ringworm or athlete’s foot. Many people use antifungal creams on the nail for weeks with no change and conclude nothing works. Understanding why helps you stick with the right plan.

What does nail fungus look like?

Common signs include:

• White, yellow, brown or greenish discolouration of the nail
• Thickening that makes nails hard to cut
• Crumbly, brittle or ragged edges
• Lifting of the nail from the nail bed (onycholysis), with debris collecting underneath
• White, chalky patches on the surface in some types
• Discomfort or pain in shoes, especially with thick big toenails
• Sometimes a mild odour

Toenails, especially the big toenail, are affected much more often than fingernails. Usually only one or a few nails are involved at first, and the infection may slowly spread to others.

What causes nail fungus?

Most nail fungus is caused by dermatophytes, the same fungi that cause ringworm and athlete’s foot. Yeasts (such as candida) and certain moulds can also infect nails, especially fingernails of people whose hands are often in water.

Risk factors include:

• Athlete’s foot or ringworm elsewhere on the body
• Closed shoes and socks for long hours, sweaty feet, and hot, humid weather
• Walking barefoot in shared bathrooms, gyms and pool areas
• Nail injury, including from tight shoes or sports
• Diabetes, poor circulation or reduced immunity
• Older age, as nails grow more slowly
• Hands frequently in water, such as for household work, cooking and washing, which can lead to candida infection around the nails

Is it really nail fungus?

Many nail conditions look alike, and studies suggest that a large share of abnormal looking nails are not fungal at all.

Condition	Clues
Nail fungus	Thick, yellow or brown, crumbly nail, often starting at the tip, often with athlete’s foot
Nail psoriasis	Tiny pits, oil drop discolouration, lifting, often with psoriasis on the skin or scalp
Trauma	One nail, often the big toe, history of injury or tight shoes
Lichen planus	Thinning, ridging and splitting, sometimes nail loss
Candida paronychia	Swollen, sore nail fold with nail changes, common in people doing wet work
Melanoma (rare)	A dark streak that widens, or spreads to the skin around the nail

Your dermatologist may take a nail clipping or scraping for a KOH test under the microscope, a fungal culture, or a laboratory examination of the clipping. Starting months of oral treatment without confirmation is not recommended. If your nails show pits and you have scaly skin patches, our guide on psoriasis symptoms and treatment may help, and nail changes with an itchy rash may also be linked to lichen planus.

Why is nail fungus so slow to treat?

• Nails grow slowly. Fingernails take roughly six months to grow out fully, and toenails can take a year or longer.
• The fungus lives under and within the nail plate, where creams struggle to reach.
• Damaged nails stay visible even after the fungus is gone, until healthy nail grows out.
• Reinfection from untreated athlete’s foot or damp shoes is common.

So even when treatment is working, the nail may look unchanged for months. Judging success too early is one of the main reasons people stop treatment.

How is nail fungus treated?

The plan depends on how many nails are affected, how much of each nail is involved, the type of fungus, your age, other medicines and health conditions. The Nail Society of India has published recommendations to guide doctors in the Indian setting.

Your dermatologist may consider:

• Topical antifungal nail lacquers or solutions for mild infection limited to the tip of one or a few nails. These are applied for many months.
• Oral antifungal medicines for more extensive infection, several nails, or involvement near the base of the nail. These work from inside and are usually taken for a set period, sometimes with blood tests. Not everyone can take them, particularly people with liver problems or certain other medicines.
• Combination treatment with both oral and topical medicines.
• Trimming, filing and thinning the nail to reduce thickness and help topical medicines penetrate.
• Removal of a badly damaged nail in selected cases.
• Treating athlete’s foot and skin ringworm at the same time.

Lasers and light based treatments are offered in some clinics, but evidence for clearing infection is still limited and results vary.

Please do not take oral antifungal tablets without a prescription, and do not repeat an old prescription on your own. Incomplete or wrong courses may contribute to treatment failure and resistance, which is already a concern with fungal infections in India, as discussed in our guide to ringworm and tinea in India.

How can I prevent nail fungus from coming back?

1. Keep feet clean and dry, especially between the toes, after bathing.
2. Treat athlete’s foot early and fully.
3. Wear breathable footwear, alternate shoes, and let them dry in sunlight.
4. Change socks daily, or more often if your feet sweat; cotton socks are a good choice.
5. Wear slippers in shared bathrooms, gyms and hostels.
6. Keep nails short and straight, and use your own clippers.
7. Avoid sharing towels, shoes and nail tools.
8. Wear gloves for wet work at home, with cotton liners if your hands sweat.
9. Manage diabetes well and check your feet regularly.

If sweaty feet are a constant problem, our article on hyperhidrosis and excessive sweating explains treatment options.

Is it safe to use nail polish or visit a nail salon?

Regular nail polish does not treat fungus, and wearing it all the time can hide changes in the nail and trap moisture. Some medicated nail lacquers are designed to be applied like polish, but these are a treatment, not a cosmetic, and should be used as your doctor advises. If you visit a salon for a manicure or pedicure, choose one that sterilises its tools or carry your own, and avoid aggressive cutting of cuticles, which can let infection in. Foot spas and tubs that are not cleaned well between clients can also spread infection.

When to see a dermatologist

See a dermatologist if:

• A nail is thick, discoloured, crumbling or lifting.
• Nail changes are spreading to other nails.
• You have diabetes, poor circulation or reduced immunity.
• A nail is painful, or the skin around it is red, swollen or has pus.
• There is a dark streak in the nail that is new, changing or spreading.
• You have used nail treatments for months without improvement.

Nail fungus needs patience and the right plan from the start. Dr. Maria offers online consultations to review your nails and history, and to advise whether testing and treatment are needed.