Nail fungus is a slow infection of the nail itself, usually a toenail. It makes the nail thick, yellow-brown, crumbly and lifted away from the skin underneath. It is treatable, but treatment is measured in months, because the damaged nail has to grow out before anything looks better. Green discolouration associated with Pseudomonas bacteria under a damaged or lifted nail.
The same eight facts on every condition comparison.
Distal subungual onychomycosis The most common type, starting at the tip.
White superficial onychomycosis Chalky white patches on the nail surface.
Proximal subungual onychomycosis Starts near the cuticle; rarer.
Candidal nail infection Caused by yeast, usually on fingernails.
Green Nail Syndrome A green-blue patch occupies much of the nail plate.
Fungi invade the keratin that makes up the nail, often entering near an edge or a small break. Damage and debris can make the nail discolored, thickened or separated from its bed.
Bacteria grow in a moist space beneath a nail that has separated from its bed. Their pigment colors the affected area green rather than changing the nail through fungal infection alone.
Nail Fungus. Can occur at any age but becomes more common in older adults.
Green Nail Syndrome. Can occur after nail damage at any age.
Nail fungus is caused by fungi, usually the same ones behind athlete's foot. They get into the nail through small cracks or the skin around it, then grow slowly.
Bacterial pigment colours a moist space beneath a separated nail plate.
Some families are more prone to fungal nail infections, likely because of inherited differences in skin immunity.
Evidence labels come from each condition’s own treatment list.
A strong urea cream or patch softens a thick nail so more of it can be filed or cut away. It kills nothing on its own. Its job here is to reduce the amount of dense nail sitting between a painted-on treatment and the fungus, and to make an uncuttable nail manageable.
This will not cure the nail, but it clears the athlete's foot on the skin that keeps reseeding it. Use it on the whole sole and between the toes, not just the itchy bit, and carry on for a week or two after the skin looks normal. Treating the skin is the single cheapest thing you can do to stop the nail coming back after a course of tablets.
It does have antifungal activity in the laboratory, and the small studies in nails have shown some improvement in appearance. None have shown reliable cure of an established nail infection. It also cannot get through a thick nail, and it can irritate the skin around it.
Jublia. A solution painted on the nail once a day for about a year. It penetrates nail better than the older lacquers, and it suits mild infection, one or two nails, or people who cannot take tablets. Complete cure rates are still well below tablets, so it is a reasonable choice rather than the strongest one.
Kerydin. Another daily paint-on solution used for about a year, with a small molecule that gets through the nail plate. Results are similar to the other topicals: many nails look better, far fewer clear completely. It works best on thin nails with the infection limited to the tip.
Penlac. The oldest of the prescription nail paints, applied daily with the built-up layers removed weekly with alcohol. Complete cure rates are low, in single figures in the original studies. It is cheap and safe, and it is mostly used when tablets are not an option.
A clinician can select a suitable treatment if drying and addressing the nail problem are insufficient.
The first choice for dermatophyte nail infection and the option with the best cure rate: usually 12 weeks for toenails and 6 for fingernails. It binds into the nail and keeps working there for months after the last tablet. A liver blood test is standard, taste changes are a known side effect, and nothing will look different while you are taking it.
The main alternative, and the better option when a yeast or a mould is grown rather than a dermatophyte. It is often given as pulses, a week on and three weeks off. It interacts with a long list of common medicines and is avoided in some heart conditions, so your doctor needs everything you take, including anything bought over the counter.
Taken once a week rather than daily, which suits people who struggle with a long daily course. Cure rates sit below terbinafine and it usually has to be continued until the nail has grown out, which can be a year. It also interacts with a number of other medicines.
The old antifungal tablet, now largely replaced for nails. It needs 12 to 18 months of daily treatment, it clears fewer nails than terbinafine, and relapse afterwards is common. It is still occasionally used in children or when the newer drugs cannot be taken.
Thinning and clipping the nail. Cutting the nail back and filing or drilling down the thickened part, usually by a podiatrist. It is painless and it does two things: it takes pressure off a sore toe, and it removes dense nail and any packed clump of fungus that medicine cannot get through. Done alongside tablets or a nail paint, it makes them work better; done alone, it does not treat the infection.
Laser devices are cleared to temporarily increase the amount of clear nail, which is not the same thing as curing the infection. Studies are small, short and mostly measure appearance rather than clearance, and the fungus commonly returns. It is usually several sessions, paid for out of pocket, and it is a reasonable thing to consider only when tablets are genuinely not an option.
Removing the nail. Taking off part or all of the nail, either surgically or with a strong urea paste. It is not a cure on its own, because the fungus is also in the nail bed and the new nail grows back into it. It is kept for a nail that is painful, hopelessly thick, or holding a dense clump of fungus, and it is done alongside tablets rather than instead of them.
Nail fungus does not clear on its own. Left alone it takes over more of the nail and, over years, more nails. Once treatment starts, nail growth sets the timeline, so watch the base.
The discoloration improves as the affected nail grows out and the moist, damaged nail environment is addressed. Recovery takes time; recurrence is possible if nail lifting or moisture persists.
Cellulitis
A thickened, cracked nail and the split skin around it give bacteria a way into the leg. The result is a spreading area of hot, swollen, tender skin, usually with feeling unwell and a fever, and it needs antibiotics quickly. It matters most for people with diabetes, poor circulation in the legs or a weakened immune system, which is why fungal nails are treated more actively in those situations.
Spread to other nails and the skin
Left alone, one infected nail slowly seeds the others, and the same fungus keeps the skin of the sole and the gaps between the toes scaly and itchy. This is athlete's foot and nail fungus feeding each other. Treating the nail while ignoring the skin is the usual reason people end up doing the whole course twice.
Permanent nail damage
If the infection has been there for years, the tissue that makes the nail can be scarred by the time it clears. The nail then grows back ridged, short or misshapen even though the fungus is gone. It is not common, and it is a reason to treat sooner rather than later rather than a reason to expect it.
It may coexist with other nail disease; colour alone does not identify every cause.
Confirm the diagnosis before long treatment courses. Seek care sooner for diabetes, poor circulation, painful swelling or infection around the nail.
Seek care for pain, spreading inflammation, diabetes or immune suppression, or persistent discolouration.
Longer than almost anyone expects. The medicine protects new nail as it forms, and a toenail takes roughly 12 to 18 months to replace itself, a fingernail about 4 to 6. Progress is a widening band of clear nail at the cuticle, not the tip.
It depends how much nail is involved. Prescription topicals suit mild infection, one or two nails, or when tablets are not suitable, and they avoid blood tests. Cure rates are distinctly lower and they need daily use for close to a year. For thick nails, several nails, or infection at the cuticle, tablets are what work.
Most healthy adults tolerate them well and serious problems are uncommon. Terbinafine can affect the liver, so a blood test before or during the course is standard, and taste changes are common. Itraconazole interacts with a long list of medicines and is avoided in some heart conditions. Your doctor needs a full list of what else you take.
While you are being tested, no - polish makes sampling harder and hides what is happening. During treatment it is not forbidden, but it hides the new nail you are meant to be watching, and gel removal damages the plate. Going bare is more useful.
It can, and in a meaningful number of people it does. The strongest protection is not another course of tablets - it is treating the athlete's foot, keeping feet dry, rotating shoes, and wearing something in communal wet areas.
It spreads within a household more than between strangers - shared floors, towels, bath mats and clippers. Use your own clippers and file, keep a separate foot towel, and treat any athlete's foot in the house. Ordinary contact is very unlikely.
Green discolouration associated with Pseudomonas bacteria under a damaged or lifted nail.
Keep the nail dry, avoid artificial coverings and avoid digging under it.
Seek care for pain, spreading inflammation, diabetes or immune suppression, or persistent discolouration.
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