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. Nail psoriasis is psoriasis affecting the nails. It causes pitting, lifting, crumbling, and yellow-brown patches under the nail. It is often mistaken for a fungal infection, and it improves slowly because a nail has to grow out before you can see the result.
The same eight facts on every condition comparison.
Several organisms can cause it.
Dermatophytes, yeasts or molds can invade nail keratin.
It is not always trivial.
Thickened nails can be painful in shoes and affect mobility.
Testing confirms it.
Nail clippings help distinguish infection from trauma, psoriasis and other nail disease.
Some changes are not fungus.
A new dark band, bleeding or destructive change should be examined, not assumed fungal.
It is psoriasis of the nail unit.
Inflammation affects the structures that make and support the nail.
Different parts cause different signs.
Matrix involvement causes pitting; nail bed involvement causes lifting and thickening.
Lookalikes are common.
Trauma and fungal infection can resemble or coexist with it.
Treatment looks beyond appearance.
Pain, function and psoriasis elsewhere guide care.
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.
Pitting Tiny dents in the nail surface.
Oil drop spots Yellow-brown patches under the nail.
Lifting The nail separates from the bed.
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.
Psoriasis-related inflammation can affect both the nail matrix, where the nail grows, and the nail bed beneath it. This alters nail formation and attachment, causing features such as pits, debris, discoloration or lifting.
Nail Fungus. Can occur at any age but becomes more common in older adults.
Nail Psoriasis. Can occur at any age with psoriasis and may occasionally precede visible skin disease.
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.
Nail psoriasis is psoriasis that affects the cells that build the nail. The same immune overreaction that causes skin plaques disrupts how the nail grows.
Some families are more prone to fungal nail infections, likely because of inherited differences in skin immunity.
It shares the same inherited tendency as skin psoriasis.
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.
A strong urea cream softens a thick, crumbling nail so the lifted part can be trimmed back to where it is still attached. That removes the pocket where debris collects and stops the nail catching. It treats none of the psoriasis, and it is used alongside a prescription rather than instead of one.
Biotin is widely sold for nails, and it has been studied mainly in brittle nails rather than in psoriasis. It does nothing about the inflammation that is damaging the nail here. Unless you are actually deficient, which is rare, this is not treatment for nail psoriasis.
Ordinary polish is allowed and many people use it to cover discoloration, which is a reasonable thing to want. It also adds a thin layer of protection to a fragile nail. Gels and acrylics are the ones to avoid, because of the filing, soaking and removal rather than the color.
Rubbed into the nail folds and the nail itself at night, it keeps the skin around the nail from cracking and makes a brittle nail less likely to split. It does nothing to the inflammation underneath. Its real value here is that it protects the seal around the nail, which is the part you can influence without a prescription.
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.
Clobetasol Propionate. A strong steroid, applied to the skin of the nail folds rather than to the nail, because that is where it can reach the matrix underneath. It is the usual first prescription and it helps pitting and ridging most. It is used in courses rather than continuously, since long unbroken use thins the skin around the nail.
A vitamin D treatment that works best on the nail bed problems — the chalky buildup that thickens and lifts the nail. It is often paired with a steroid, or alternated with one, so the steroid can be rested. Expect months, not weeks, and judge it on the new nail at the base.
A retinoid applied around and under the edge of the nail, studied in small trials that showed some improvement in lifting and pitting. It is a reasonable third option when steroids have not been enough. It commonly irritates the skin of the nail folds, and it is not used if you are pregnant or trying to be.
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.
A tablet with nail results measured directly in its trials, which is more than can be said for most options. It suits people who want something systemic without blood test monitoring. Nausea, loose stools and headache are common in the first few weeks and usually settle, and nail improvement is judged at six months, not six weeks.
A newer daily tablet for moderate to severe psoriasis, with nail improvement recorded in its studies alongside the skin. It is an option when a tablet is preferred to an injection. It is expensive, and it usually has to be approved by insurance after other treatments have been tried.
An old, cheap weekly tablet that helps nails and also helps psoriatic arthritis, which is why it is often chosen when the joints are involved too. It needs regular blood tests, folic acid alongside it, and no alcohol excess. It is not used in pregnancy, and it must be stopped well before trying to conceive.
It works quickly and can improve badly affected nails, but nails take a year to show it, and cyclosporine is only meant for short stretches because of its effect on blood pressure and the kidneys. That mismatch is why it is rarely the choice for nails alone. It is mainly used to settle severe psoriasis while something longer-term is started.
An injection given every other week, and one of the treatments with the best measured results in nails specifically. It also treats psoriatic arthritis, so it is a common choice when nails and joints are both involved. It needs screening for tuberculosis and hepatitis before starting, and it slightly raises the risk of infections.
A newer biologic given every twelve weeks after the first doses, which suits people who do not want frequent injections. Nail clearance in its trials was substantial, though it lagged the skin by several months, exactly as nail growth predicts. Screening before starting is the same as for the other biologics.
Steroid injection in nail fold. Small injections into the skin at the base of the nail, placing the steroid right over the matrix. It is the most effective option for pitting and ridging in one or two stubborn nails, repeated every four to six weeks for a few rounds. It stings, and it is impractical when many nails are involved.
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.
Removing the nail. Taking the nail off does not treat the inflammation underneath, so the replacement nail grows back with the same disease in it. It is also painful and leaves the fingertip unprotected for months. It is done occasionally for a specific problem, but it is not a treatment for nail psoriasis.
Light treatment works well for psoriasis on the skin, but the nail plate blocks most of the light from reaching the matrix and nail bed beneath it. Nails are the area where phototherapy performs worst. It is worth having for widespread skin psoriasis, but do not expect it to be the thing that fixes the nails.
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.
Nail psoriasis moves on the nail's timescale. With treatment a healthy band appears at the base and pushes the damaged nail forward, so progress is judged at the cuticle. Months, not weeks.
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.
Psoriatic arthritis
Nail psoriasis is strongly linked with arthritis in the joint nearest the nail, because the nail unit and that joint sit closer together than they look. It shows as joint pain, a whole finger or toe swelling up like a sausage, or morning stiffness lasting more than half an hour. It is worth reporting early rather than waiting it out, because treating it early is what protects the joints.
Infection under a lifted nail
Once a nail has lifted, the gap underneath is a warm, damp space that yeast, bacteria and fungus are happy to occupy. That adds green, brown or black discoloration and sometimes an odor on top of the psoriasis, and the nail stays discolored until both are treated. Trimming the lifted part back removes the pocket; digging underneath with a sharp tool makes it bigger.
Permanent nail scarring
If the matrix is inflamed hard enough for long enough, the tissue that makes the nail can be scarred, and the nail then grows back ridged, short or misshapen even after the psoriasis is controlled. It is uncommon, and it usually follows years of severe untreated disease. It is a reason to treat rather than something to expect.
Hiding your hands
This is the part of psoriasis people apologize for. Nails are hard to cover and awkward to explain, and lifted or crumbling nails also make buttons, keyboards, zips and picking up small things genuinely harder. It is a fair reason to ask for treatment, and it is worth saying out loud at the appointment, because how much a nail bothers you changes what is reasonable to offer.
Confirm the diagnosis before long treatment courses. Seek care sooner for diabetes, poor circulation, painful swelling or infection around the nail.
Seek assessment for new nail changes or painful swollen joints. Nail samples may be needed because fungal infection can look similar or coexist.
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.
They look similar, and the only reliable way to tell is a clipping sent for testing. Some features lean toward psoriasis - pitting across several nails, an oil-drop patch, psoriasis elsewhere - but none are proof. You can have both at once, which is why testing first is worth it.
Often it gets close, and many nails return to normal. The visible nail cannot be repaired, so improvement comes as healthy nail grows from the base. Nails severely affected for years are least likely to fully recover, and permanent scarring is possible but uncommon.
You are waiting on nail growth, not on the medicine. A fingernail grows about three millimeters a month and replaces itself in roughly six months; a toenail can take a year or more. Treatment works on the new nail immediately, but that nail is still under the skin.
Regular polish is fine and a reasonable way to cover discoloration. Skip gels and acrylics, and ask that cuticles are not cut or pushed back - that skin sits over the part that makes the nail, and injuring it can worsen the psoriasis.
No, but nail involvement raises the chance, especially arthritis in the joint nearest the nail. That is a reason to mention joint symptoms early, not to worry. Joint pain, a swollen finger or toe, or morning stiffness lasting more than half an hour should be assessed, because early treatment protects the joints.
Almost never. Removing a nail does not treat the inflammation underneath, the replacement grows back with the same disease, and it is painful. It is occasionally done for a specific problem, but not as treatment.
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