Condition

Ringworm

Ringworm is a common fungal skin infection that spreads outward in a scaly ring with a raised edge. There is no worm involved. It clears with antifungal treatment, as long as the treatment is used for long enough and steroid creams are kept away from it.
Dr. Schwarz, MD · Board-certified dermatologistLast reviewed September 8, 2026

Start here

There is no worm — the name describes the ring shape of the rash, not the cause. It is a fungus, the same family that causes athlete's foot, and it is very common. Do not put hydrocortisone on it; steroid cream eases the itch for a few days while the fungus spreads underneath, and the rash that returns is bigger, less ring-shaped and harder to identify. The other common mistake is stopping too soon — the patch looks fine well before the fungus is gone, so keep the cream going a week or two after it looks clear.

— Dr. Schwarz, Board Certified Dermatologist

Key Facts

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How commonVery common - fungal skin infections are among the most frequent skin infections worldwide
Who gets itAnyone. More likely in warm humid conditions, in contact sports, and with close contact with pets or other people
Curable or managedCurable - it clears with antifungal treatment and does not stay in the body afterward
Prescription neededUsually not for a small patch on the body. Scalp and nail infections need prescription tablets
Time to improveItching settles within days. The patch usually clears in 2 to 4 weeks, and treatment should continue past that

What It Is

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Ringworm is a skin infection caused by fungi called dermatophytes. They live in the dead outer layer of skin and feed on keratin, the protein in skin, hair and nails. Nothing burrows, and nothing lives under the skin.

The classic patch is round or oval and itchy, with a raised scaly edge and a flatter center. It spreads outward from where it landed, so the middle settles while the edge advances — that is the ring. Not every case looks like one: on the face, in folds and after steroid cream, ringworm can be shapeless and mistaken for eczema.

The same infection gets a different name in each place. On the body it is tinea corporis — what most people mean by ringworm. In the groin, tinea cruris or jock itch. On the feet, tinea pedis or athlete's foot. On the scalp, tinea capitis; in the nails, tinea unguium; on the face, tinea faciei; on the hands, tinea manuum. Same fungi, different address — and different treatment, since scalp and nail infections need tablets, not cream.

Ringworm is contagious. It spreads by contact with an infected person or animal, by contaminated objects such as towels, mats and clippers, and occasionally soil.

Symptoms

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A ring with a clear center

Body

A round or oval patch with a raised scaly border and a clearer middle, which spreads slowly outward. It is itchy and usually appears on the arms, legs or trunk. Steroid creams flatten the edge and make it harder to recognize.
Scaly patches with hair loss

Scalp

Scaly, itchy patches on the scalp with broken hairs or bald areas, most often in children. Sometimes a boggy, tender swelling forms. Scalp involvement needs tablets, because creams do not reach the follicle.
A ring that does not look like one

Face

A patch on the face that is often less obviously ring-shaped, with a soft edge and mild scale. It is commonly treated as eczema for weeks. A rash that expands outward while being treated with steroid cream is a clue.

How It Looks by Skin Tone

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A round patch on a forearm on fair light skin, with a raised pink scaly border and a flatter, clearer middle.A round patch on a forearm on medium olive-tan skin, with a raised tan-brown scaly border and a flatter middle. The color difference from the surrounding skin is slight.A round patch on a forearm on brown skin, with a raised scaly border a shade darker and grayer than the surrounding skin and a flatter middle. There is no redness anywhere in the patch.A round patch on a forearm on deep dark brown skin. The raised scaly border is barely darker than the skin around it, and the flatter middle is visible mainly by its smoother texture.
LightMediumBrownDeep

On deeper skin tones the ring is often not red. It can look brown, gray, violet or just darker than the surrounding skin, so looking for redness is the wrong approach. The reliable signs are the raised scaly border, flatter middle, defined edge and itch.

Because the color cue is weaker, it is more often treated as eczema for a while — and the usual eczema treatment is a steroid cream, which makes fungal infections spread. If a patch called eczema improves for a few days on steroid cream then returns larger, ask about testing for fungus. After it clears, flat dark marks along the old border are common and can take months to fade. That is post-inflammatory hyperpigmentation, not infection, and needs no more antifungal cream. Daily sunscreen helps. Tinea capitis, the scalp form, is seen more often in children with tightly coiled hair, where shared combs, brushes and clippers spread it. It shows as scaly patches with broken hairs or bald areas rather than a ring, and always needs oral treatment — cream cannot reach fungus inside the hair shaft.

Where It Shows Up

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Front view of a whole body with red marks on both arms, across the chest and abdomen and on both thighs.
Arms, legs and trunk
Ringworm lands wherever the fungus was picked up — from a pet, a mat, a towel or another person — so the arms, legs and trunk are the usual places. The shape matters more than the site: a ring that spreads outward with a raised scaly edge and a calmer middle.
Front view of a whole body with red marks across the groin and inner thighs, around the waistline and on both feet.
Groin, feet and under tight clothing
Warm, damp areas are easier for it to hold: the groin, the feet and between the toes, and skin under tight sportswear. The same fungus moves between these sites, so treating one and not the other is why it keeps coming back.
Front view of a head with red marks across the scalp, on both cheeks and along the beard area of the jaw.
Scalp and beard
On the scalp it is mostly in children, and it causes a scaly patch with broken-off hairs rather than a clean ring. Scalp and beard ringworm need tablets — creams do not reach the fungus down in the follicle.

What Happens in the Skin

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This is what is going wrong under the skin, in the order it happens. Click a step to see it.

How Ringworm happens
Skin basics
BARRIEREPIDERMISDERMIS0NORMAL SKIN1THE FUNGUS ARRIVES2IT SPREADS OUTWARD3THE IMMUNE REACTION MAKES THE RING

The outer layer sheds steadily and there is nothing living in it.

From another person, a pet, soil or a shared towel or mat. It settles in the dead outer layer.

The fungus grows evenly in every direction from where it landed, using up the keratin as it goes and leaving the older center behind.

The skin reacts hardest where the fungus is newest, at the advancing edge - so the rim is raised, scaly and itchy while the middle looks almost normal. It is not a worm.

The outer film of dead cells and oil. It holds water in and keeps irritants out, and it is thinner than a sheet of paper. Almost every dry, itchy, stinging skin problem starts here.

The outer layer, and the only one anything in a jar reaches. It renews itself constantly: a cell made at the bottom takes about a month to reach the surface and flake off. Most of what a skincare product does, it does here.

The living layer underneath, holding the blood vessels, the nerves and the collagen. It is where lasting change happens and it is hard to reach: most of what is sold for the skin never gets this far.

Four things happen, in order. Dermatophyte fungi — most often Trichophyton, sometimes Microsporum or Epidermophyton — land on skin from another person, an animal, a shared object or soil. They need warmth and moisture to take hold, which is why sweat, damp clothing and occlusive shoes matter. Once established they release enzymes that digest keratin in the dead outer layer and spread outward in a circle from that point. The immune system reacts at the advancing edge, producing the scale, raised border and itch, while the older center quiets down.

So the ring is not the shape of the fungus but of an infection growing outward from one point, newest and most active at the rim. That is why cream should go a couple of centimeters past the visible edge — the fungus is already in skin that looks normal.

Risk Factors

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Ringworm is about exposure and conditions, not cleanliness. Get the fungus onto warm, damp skin and it grows.

How it spreads
Contact sports
Wrestling, judo and rugby spread it skin to skin, commonly enough to have its own name.
How it spreads
Shared surfaces and objects
Locker room floors, gym mats, towels, bedding, hats, hairbrushes, barber clippers.
How it spreads
Pets and farm animals
Kittens and puppies are a frequent source, often with only a small patch of thin fur. Guinea pigs and cattle too.
Environment & clothing
Warm, humid weather and heavy sweating
The biggest environmental factor. Cases rise in summer.
Environment & clothing
Occlusive clothing and footwear
Tight synthetic sportswear, work boots, and staying in damp clothes after exercise.
Other health conditions
Untreated athlete's foot or fungal nails
A reservoir that reseeds the groin, hands and body, and a leading reason it keeps returning.
Other health conditions
Diabetes and a weakened immune system
Both make fungal infections likelier, wider and more stubborn.
Other health conditions
Topical steroid use
Steroid creams on an undiagnosed rash suppress the local immune response, letting a small patch get large.
Age
Children
Scalp ringworm is largely a childhood infection, spreading easily within a household or class.

Course

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Untreated, ringworm expands slowly rather than resolving. Treated, it is predictable. Scalp and nail infections run much longer and need tablets — weeks for the scalp, months for nails, which have to grow out.

Days 4 to 14 after contactStarting
A small spot appears

A small itchy pink, brown or gray spot where the fungus landed. Easy to miss.

Weeks 1 to 3Spreading
The ring shape appears

The spot widens into a round patch with a scaly, slightly raised border and flatter center. It may itch a lot or barely at all. New patches appear if hands, towels or clothes spread it.

Days 2 to 7 of treatmentSettling
The itch eases first

With an antifungal cream the itch improves within a few days and the border starts to flatten.

Weeks 2 to 6 of treatmentClearing and finishing
Looking clear is not the same as clear

The scale goes and the patch fades. This is where most people stop. That is why it returns — the fungus can still be in skin that looks normal. Keep the cream on one to two weeks past clear.

After clearingMarks
A flat mark can stay behind

A flat pale or dark mark can stay for weeks to months, especially on deeper skin tones. Not active infection.

What Makes It Better & Worse

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Ringworm is four problems at once — picking up the fungus, warmth and moisture letting it grow, spread through the skin, and the immune reaction behind scale and itch. Most treatment failures are not about the wrong cream — they are an untreated source, moisture nobody fixed, or a course stopped two weeks early.

What is driving yours?

FATBARRIEREPIDERMISDERMIS

From another person, a pet, soil or a shared towel or mat. It settles in the dead outer layer.

The fungus grows evenly in every direction from where it landed, using up the keratin as it goes and leaving the older center behind.

The skin reacts hardest where the fungus is newest, at the advancing edge - so the rim is raised, scaly and itchy while the middle looks almost normal. It is not a worm.

What helps

  • Wash and separate towels and bedding Hot wash, no sharing until it clears.
  • Have the pet checked Animal ringworm often shows as thin or crusty fur.
  • Treat the feet and nails too Otherwise they reseed it.
  • Shower and change soon after sport The single best habit if you train.

What makes it worse

  • Sharing household items Towels, bedding, clothes or hairbrushes pass it on.
  • Walking barefoot Communal showers and pool areas are a classic route.
  • Not treating the pet If an animal is the source, treating only people means it returns.
  • Contact sport before it is treated Very transmissible skin to skin.
  • Untreated athlete's foot or nail fungus A permanent source for the body.

What helps

  • Keep the area dry Dry thoroughly, change sweaty clothes, wear loose cotton.

What makes it worse

  • Staying in damp clothes Fungi need moisture. The easiest thing here to fix.
  • Tight, occlusive clothing over the patch Traps heat and sweat over the fungus.

What helps

  • An over-the-counter antifungal cream Terbinafine, clotrimazole, miconazole, ketoconazole.
  • Treat past the edge A couple of centimeters past the border, one to two weeks past clear.
  • Oral antifungal tablets when needed Scalp and nail infections, and stubborn cases.
  • Give it a fair trial, not an endless one Expect improvement within two weeks, or be seen.
  • Avoid steroids on an undiagnosed rash If you have used one, say so.

What makes it worse

  • Stopping treatment when it looks clear Skin clears before the fungus does.
  • Steroid creams Calm the itch while the fungus spreads underneath.
  • Scratching Breaks the skin and carries fungus to new sites.

How These Treatments Work

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Treatments for Ringworm do not all work in the same place. Tap one to see where it acts.

Pick a treatment
Skin basics
BARRIEREPIDERMISDERMISKILLS THE FUNGUSTREAT WIDER THAN YOU SEEKILLS THE FUNGUSSTOPS REINFECTION

On the body, two to four weeks.

It grows outward, so the active fungus is at the ring and just beyond it.

Needed on the scalp, where a cream cannot reach down the follicle.

Cats, kittens and other people in the house pass it back.

The outer film of dead cells and oil. It holds water in and keeps irritants out, and it is thinner than a sheet of paper. Almost every dry, itchy, stinging skin problem starts here.

The outer layer, and the only one anything in a jar reaches. It renews itself constantly: a cell made at the bottom takes about a month to reach the surface and flake off. Most of what a skincare product does, it does here.

The living layer underneath, holding the blood vessels, the nerves and the collagen. It is where lasting change happens and it is hard to reach: most of what is sold for the skin never gets this far.

Over-the-Counter Products

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Everything here you can buy without seeing anyone.

16:9 hero for Terbinafine. Never cropped: the tone strip and the corner logo depend on the full frame.
Terbinafine cream
Strong evidence
The most effective cream you can buy for ringworm on the body, and it kills the fungus rather than just stopping it growing, so the course is shorter — often one to two weeks. Take it a couple of centimetres past the visible edge. It does not work on the scalp or the nails, where the fungus sits out of reach.
Clotrimazole or miconazole
Clotrimazole or miconazole
Strong evidence
The familiar azole creams, sold everywhere and cheap. They work well on body ringworm, but they stop the fungus growing rather than killing it, so they are used twice a day for two to four weeks and for one to two weeks after the skin looks clear. Stopping at the point it looks better is the usual reason it returns.
Tolnaftate
Tolnaftate
Moderate evidence
An older antifungal, most often sold as a powder or spray. It works on body and foot ringworm but more slowly than terbinafine, and it is weaker on stubborn patches. Its real use is keeping the feet and shoes dry after treatment, since untreated feet are what reseed the rest of the skin.
Five dark glass tea tree essential oil bottles with glass droppers and one green box on white16:9 hero for Tea Tree Oil. Never cropped: the tone strip and the corner logo depend on the full frame.
Weak evidence
It does have some antifungal activity, and it is the home remedy people ask about most. The trouble is that it clears ringworm far less reliably than a pharmacy cream, it commonly irritates the skin, and weeks spent on it are weeks the patch keeps spreading. There is no reason to choose it over a proven cream that costs about the same.
A plain white ointment tube lying on its side, labeled Hydrocortisone with a blue swoosh16:9 hero for Hydrocortisone. Never cropped: the tone strip and the corner logo depend on the full frame.
Never use
It takes the itch away for a few days, and that is exactly the problem. Steroid cream damps down the immune reaction that was holding the fungus at the edge, so the infection spreads while the rash looks better. What returns is bigger, shapeless and harder to recognize. Do not put it on an undiagnosed rash.

Prescriptions

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These need a prescription.

16:9 hero for Ketoconazole. Never cropped: the tone strip and the corner logo depend on the full frame.
Ketoconazole 2% cream
Strong evidence
The prescription strength of a familiar antifungal, used for body ringworm that has not cleared on an over-the-counter cream, and for larger patches. It is applied once or twice a day for two to four weeks. Like every cream, it is the wrong tool for the scalp and nails.
A white cream tube lying on its side on a white background, with a plain white label reading Ciclopirox and a blue swoosh beneath it.
Ciclopirox cream
Moderate evidence
A broad antifungal that also settles inflammation a little, which suits an angry, very itchy patch. It is a reasonable choice when azole creams have not worked or have irritated the skin. It still needs the full course and the same treating past the edge.
A white cream tube lying on its side on a white background, with a plain white label reading Econazole and a blue swoosh beneath it.
Econazole cream
Moderate evidence
A prescription azole cream used much like clotrimazole, applied once daily for two to four weeks. It has some activity against bacteria as well, which is occasionally useful in a moist fold or between the toes where both are present.
A white cream tube lying on its side on a white background, with a plain white label reading Steroid + Antifungal and a blue swoosh beneath it.
Steroid–antifungal combinations
Never use
Creams that mix an antifungal with a strong steroid are widely prescribed and are a poor choice for ringworm. The steroid part lets the fungus spread and thins the skin, particularly in the groin, and cure rates are lower than with an antifungal alone. If you have one at home, check the label before using it here.
16:9 hero for Terbinafine. Never cropped: the tone strip and the corner logo depend on the full frame.
Terbinafine tablets
Strong evidence
The usual tablet for ringworm that cream cannot reach — scalp infections, nails, widespread patches and stubborn cases. Typically two to four weeks for the scalp and several months for nails, because the nail has to grow out. Liver blood tests are checked for longer courses, and it interacts with a number of other medicines.
An amber prescription bottle lying on its side on a white background with a plain white label reading Itraconazole, and six small round white tablets spilled out in front of it.
Itraconazole
Strong evidence
An equally effective alternative, often used for nails, for widespread infection and for cases that have not responded to terbinafine. It is sometimes given in pulses of one week a month. It interacts with a long list of common medicines, including statins and some heart drugs, so bring your full list to the appointment.
An amber prescription bottle lying on its side on a white background with a plain white label reading Griseofulvin, and six small round white tablets spilled out in front of it.
Griseofulvin
Strong evidence
The oldest scalp treatment and still a first choice in children for some species of fungus. It needs six to twelve weeks, and it is absorbed much better when taken with a fatty meal. Newer tablets work faster, so which one is used depends on the species the lab identifies.
16:9 hero for Fluconazole. Never cropped: the tone strip and the corner logo depend on the full frame.Diagram: how Fluconazole works in the skin
Moderate evidence
A once-weekly tablet, used mainly when terbinafine and itraconazole do not suit. It clears dermatophyte infections less reliably than either, so it is a second-line option here rather than a first choice, even though it is the antifungal most people have heard of.

Procedures

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These are done in the office, usually over several visits.

No procedures listed yet.

When to See a Dermatologist

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Most small patches on the body clear with an over-the-counter cream used properly. The two places worth seeing someone for quickly are the scalp and the nails — cream cannot reach fungus inside a hair shaft, untreated scalp ringworm can cause permanent hair loss, and both need tablets. Book if two weeks of treatment has brought no clear improvement, if the rash is spreading or several patches have appeared, if it keeps returning in the same place, if it is very inflamed, blistered or oozing pus, or if you have used a steroid cream on it and it changed shape or grew. Go sooner with diabetes, a suppressed immune system, or a young child. Appearance alone is less reliable than people assume, so scale is scraped from the active border and checked under the microscope — best done before treatment starts.

— Dr. Schwarz, Board Certified Dermatologist

Complications

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Kerion and permanent hair loss

Scalp ringworm can turn into a kerion — a boggy, tender, pus-oozing swelling where the immune reaction has gone deep around the hair follicles. It happens mostly in children, and it can destroy follicles and leave a permanently bald scar. Oral antifungal tablets started early are what prevent it, which is why scalp involvement is never treated with cream.

Ringworm hidden by steroid cream

Steroid cream calms the itch and flattens the edge while the fungus keeps spreading underneath. What comes back is larger, shapeless and much harder to recognize, and it is often treated as eczema for months. If a rash improved on a steroid and then grew, say so at the appointment — it changes both the diagnosis and the test.

Nail Fungus (Onychomycosis)

Ringworm that reaches the nails thickens and discolors them and lifts the nail from its bed. It matters twice over: creams cannot reach fungus under a nail, so it needs months of tablets, and until it is treated it acts as a reservoir that reseeds the feet, groin and body again and again. This is one of the most common reasons ringworm keeps coming back.

Lookalikes

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Eczema

The round, coin-shaped form of eczema is the closest copy: itchy, scaly discs on the arms and legs. Eczema discs are scaly all the way across rather than clearing in the middle, they usually come in numbers on both sides of the body, and they do not creep outward from a point. This is the mix-up worth getting right, because eczema is treated with the steroid cream that makes ringworm spread.

Psoriasis

A single psoriasis plaque is round, scaly and sharply bordered, which is close enough to cause trouble. Psoriasis scale is thicker and silvery-white and covers the whole patch rather than sitting in a rim, and the patches are usually symmetrical — both elbows, both knees. There are normally clues elsewhere too, on the scalp, the nails or the crease between the buttocks.

Contact Dermatitis

A reaction to something touching the skin can be a neat round itchy patch — under a watch, a belt buckle or a bra hook — and it is easy to read as a ring. It has no scaly advancing rim and no clearing center, it sits exactly where the object sat, and it settles when that object is kept off. Ringworm carries on spreading regardless.

Myths

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  • "Ringworm is caused by a worm." It is not It is a fungal infection of the dead outer layer of skin. The name comes from the ring shape, described long before anyone knew the cause.
  • "You get ringworm because you are dirty." Hygiene has little to do with it. What matters is contact with the fungus and warm, damp skin to grow on. Clean, frequently showering athletes are among the likeliest to get it.
  • "Hydrocortisone will sort out the itch." It will, briefly, and that is the problem. Steroid cream suppresses the immune response containing the fungus, so it spreads while looking better. The rash that returns is larger and harder to recognize.
  • "You can stop the cream once it looks clear." The skin clears before the fungus does. Stopping there is the commonest reason ringworm comes back in exactly the same place.
  • "It always looks like a ring." Often it does not — the face, folds, the scalp, and after steroid cream. Shapeless, scaly, itchy, one-sided patches are worth checking.
  • "You can only catch it from animals." Animals are one source. So are other people, shared towels, gym mats, changing room floors, clippers and soil. Household spread is common.
  • "Changing your diet will starve it out." No good evidence that cutting sugar or anything else affects a dermatophyte infection. It responds to antifungal treatment, not diet.

Questions Patients Ask

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Is there actually a worm?

No. Ringworm is a fungal infection of the outer layer of skin, related to athlete's foot. The name describes the rash, named long before the cause was understood.

How long am I contagious?

For most body infections, much less so after a day or two of treatment. Contact sports set their own rules — wrestling commonly requires around 72 hours of treatment and the area covered. Check with your club or school rather than guessing.

Did my cat give it to me?

Possibly. Kittens and puppies are common sources, often with only a small patch of thin or crusty fur, or nothing. If a new pet arrived shortly before the rash, ask a vet to check it. Treating people and not the animal is a common reason it keeps returning.

Can I use athlete's foot cream on my body?

Yes. Same medicines — terbinafine, clotrimazole, miconazole — and the same infection elsewhere. The exception is the scalp and nails, where creams do not work whatever the tube says.

Why does it keep coming back?

Usually one of three reasons: treatment stopped as soon as the skin looked clear, an untreated reservoir such as athlete's foot or fungal toenails, or a steroid cream somewhere in the routine. Occasionally an infection really is resistant, which needs testing and a prescription.

Do I need tablets?

Not for a small patch on the body, which almost always responds to cream. Tablets are needed for scalp and nail infections, and widespread, deep or stubborn cases. That needs a doctor, partly because some oral antifungals interact with other medicines.

References

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