Ringworm (Tinea): Causes, How to Tell It from Tinea Versicolor and Eczema, Why Steroid Cream Makes It Spread, and How to Treat It Properly
Ringworm (tinea, dermatophytosis) is a fungal infection caused by dermatophytes, fungi that feed on keratin in the outer layer of the skin, the hair and the nails. It causes a red, sharply bordered, ring-shaped rash that itches and has scale along the edge. Ringworm is not caused by worms or by poor hygiene. It spreads from people, pets or contaminated soil, and it is treated with an antifungal medicine chosen to suit the body site affected.
In this article a dermatologist explains ringworm by body site (trunk, groin, feet, face, scalp, hands and nails), how to tell it apart from tinea versicolor and look-alike rashes, the creams and tablets used in medical practice with their generic names, strengths and usual duration, why some people do not get better, and the drug-resistant ringworm that is being seen more often in Asia.
What Is Ringworm and What Causes It?
Ringworm is caused by three main groups of fungi: Trichophyton, Microsporum and Epidermophyton. These fungi live only in dead keratin, so in healthy people they do not spread into the blood or internal organs, but without treatment the rash keeps slowly growing outward.
Medical names tell you the body site: tinea corporis (body), tinea cruris (groin, or “jock itch”), tinea pedis (feet, or athlete’s foot), tinea faciei (face), tinea capitis (scalp), tinea manuum (hands) and tinea unguium (nails).
Factors that help the fungus grow: damp skin and sweat, Thailand’s hot and humid weather, tight clothing, shared towels, diabetes, obesity, and the use of immunosuppressive medicine or steroid cream.
It is not a disease of people who are unclean: someone who showers twice a day can still get ringworm if they do not dry fully or keep being exposed to the fungus.
The so-called “milk ringworm” (pityriasis alba), the pale patches seen on children’s faces, has ringworm in its name but is not a fungal infection and does not need antifungal medicine. Read more in Pityriasis alba: what causes it
How Does Ringworm Spread? From People, Pets and Soil
Ringworm is contagious, but not as easily as many people fear. The fungus needs damp skin or tiny breaks in the skin to take hold. The incubation period after exposure is about 1–3 weeks before the rash appears.
Person to person: direct skin contact, or sharing towels, combs, hats or shoes. It is common in contact sports such as wrestling and judo, and in people who use communal showers.
Animal to person: cats and dogs, especially kittens, are often a source of Microsporum canis. Rashes from animals are usually more inflamed and red, and several rings may appear at once on the arms, neck or face. If a pet has patchy hair loss it needs treatment too, otherwise you will be infected again. Read more in Can you catch ringworm from a cat?
From yourself to yourself: fungus on the feet or toenails is the most common source of jock itch and of ringworm on the hands, because people scratch their feet and then scratch elsewhere, or pull underwear on over their feet.
From soil: uncommon, seen in gardeners and farmers.
Symptoms of Ringworm: The Ring-Shaped Rash
The classic look of ringworm on skin without hair is:
A round or oval red rash with a sharp border, where the edge is raised, red and scalier than the centre.
The centre fades, so the rash looks like a ring (hence “ringworm”). The rash spreads outward slowly, by a few millimetres per week.
Itching, usually worse with sweat or hot weather.
There may be small blisters or pustules along the edge, especially when the fungus comes from animals.
It is usually on one side or asymmetrical, except jock itch, which often affects both sides of the groin.
A rash that does not fit this pattern, such as an even sheet of redness with no clear border, a rash with thick silvery scale, or pale patches that barely itch, should make you think of other conditions first. These are covered in the section on differential diagnosis below.
Ringworm on the Body, Arms and Legs (Tinea Corporis)
What it looks like: a red ring-shaped rash with scale at the edge, from 1–2 cm across up to the size of a palm. Several rings may join and look like a map. It is common at the waist, under the breasts, on the back, thighs and arms.
Cause: contact with an infected person or animal, or spread from your own feet or groin. Tight clothing and trapped sweat make it spread faster.
Severity/urgency: not an emergency. If there are 1–3 small rings, they usually respond to a cream within 2–4 weeks. If it is spread over several areas or a large area, a cream alone is often not enough.
When to see a doctor: a rash wider than 2–3 palms, several patches across the body, no improvement after 2 weeks of correct antifungal use, or a rash that has changed appearance after steroid cream was used earlier.
Ringworm in the Groin, or Jock Itch (Tinea Cruris)
What it looks like: a red-brown rash in the groin and inner thighs with a sharp, raised border, often on both sides. It can spread to the buttocks or lower abdomen, but it usually does not reach the scrotum, which helps tell it apart from Candida infection.
Cause: dampness and friction. It is more common in men, athletes, people who sit for long periods, and people who also have athlete’s foot.
Severity/urgency: very itchy, and it often returns if the feet are not treated at the same time. The skin here is thin, so it is irritated by medicine more easily than elsewhere.
When to see a doctor: it comes back more than 2–3 times a year, the rash spreads to the buttocks or waist, or you have already used a steroid-containing cream. For more detail read Jock itch: what causes it and why creams do not work
Ringworm on the Feet, or Athlete’s Foot (Tinea Pedis)
What it looks like: there are 3 main types. (1) Between the toes: skin is soggy, white, peeling, itchy and smelly, usually starting between the 4th and 5th toes. (2) Moccasin type: the sole is dry and thick, with fine white scale across the sole and the sides of the foot, and it often barely itches. (3) Blistering type: itchy clear blisters on the arch of the foot.
Cause: damp feet from closed shoes and socks, and walking barefoot in communal showers or swimming pools.
Severity/urgency: it is the main reservoir of fungus that causes jock itch, ringworm of the hands and nail fungus. Cracked, soggy skin can also let bacteria in and cause cellulitis of the leg, especially in people with diabetes.
When to see a doctor: the foot is swollen, red and hot, has pus, or you have a fever; you have diabetes; or you have chronic moccasin-type disease that creams cannot reach. To tell the types of peeling feet apart, see Athlete’s foot: what causes it
Ringworm on the Face (Tinea Faciei)
What it looks like: a red rash on the cheeks, chin or forehead. The border is often less clear than on the body, and the rash often gets redder in the sun, so it is very often mistaken for a cosmetic allergy, sun rash or seborrheic dermatitis.
Cause: usually from a pet that is cuddled or kissed on the cheek, or from hands that have scratched fungus elsewhere.
Severity/urgency: this is the site where “steroid-masked ringworm” (tinea incognito) is seen most often, because people buy an anti-allergy cream themselves. The rash settles for a while and then spreads wider.
When to see a doctor: any facial rash when you are not sure what it is. A doctor should take a skin scraping before you use any medicine, especially before using a steroid cream.
Ringworm on the Scalp (Tinea Capitis)
What it looks like: round patches of hair loss with scale, hairs broken off short leaving black dots, and in some people pustules or a soft, boggy, pus-filled lump (kerion) with swollen glands at the back of the neck. It is most common in children aged 3–14 years.
Cause: spread from other children, combs, hats, pillows, or cats and dogs.
Severity/urgency: a cream alone cannot cure it, because the fungus sits deep in the hair root where creams cannot reach. Tablets are always needed. If it is left for a long time or becomes a kerion, scarring can cause permanent hair loss.
When to see a doctor: in every case, without waiting to see what happens. For treatment in children, read Scalp ringworm (Tinea Capitis)
Ringworm on the Hands and Nails (Tinea Manuum / Tinea Unguium)
What it looks like: ringworm of the hand is usually a dry, thick palm with white scale on one side only, together with both feet being affected (called “two feet–one hand”). Nail fungus makes the nail thick, cloudy yellow and brittle, with debris under the nail, and it often starts on the big toenail.
Cause: the hand that is used to scratch the feet or pick at the toenails picks up the fungus from your own feet.
Severity/urgency: a palm affected on one side only is often misdiagnosed as contact dermatitis or dry skin. Nail fungus is a source that makes skin ringworm come back, and it takes months to treat.
When to see a doctor: a one-sided peeling palm that does not clear with moisturiser, or a misshapen nail. A scraping should confirm the fungus before tablets are started, because half of all misshapen nails are not caused by fungus. Read on in Nail fungus: what causes it
How Does Ringworm Differ from Tinea Versicolor?
Ringworm and tinea versicolor are often lumped together as “ringworm and tinea versicolor”, but they are different diseases, caused by different organisms, and the medicines are not entirely the same.
The organism: ringworm is caused by dermatophyte fungi. Tinea versicolor (pityriasis versicolor) is caused by Malassezia yeast, which already lives on everyone’s skin and overgrows in hot, humid conditions.
How the rash looks: ringworm is a red ring with a clear raised edge and a paler centre. Tinea versicolor is made of small spots 3–5 mm across, white, pink or light brown, with fine powdery scale, joining into patches on the back, chest, shoulders and neck.
Itching: ringworm itches clearly. Tinea versicolor itches little or not at all.
Spread: ringworm is contagious. Tinea versicolor is hardly contagious, because the yeast is on everyone’s skin.
Treatment: tinea versicolor responds well to medicated shampoo or lotion such as ketoconazole 2%, selenium sulfide 2.5% and sodium thiosulfate 20%. Ringworm is usually treated with azole or terbinafine creams, and oral terbinafine does not work for tinea versicolor.
Skin colour afterwards: tinea versicolor often leaves pale patches for another 1–3 months even after the yeast is dead, which does not mean it has not cleared.
For full details on tinea versicolor, read Tinea versicolor: what causes it and how to tell it from vitiligo and ringworm
Conditions Often Mistaken for Ringworm
A round rash is not always ringworm, and using an antifungal for the wrong disease wastes several weeks. The conditions a dermatologist most often has to rule out are:
Nummular eczema: also round, but the whole patch is equally inflamed with no paler centre, it often weeps, and a scraping shows no fungus.
Pityriasis rosea: starts with one large oval patch (the herald patch), then within 1–2 weeks small rashes spread along the rib lines in a fir-tree pattern. It clears by itself in 6–8 weeks.
Psoriasis: sharply bordered, but with thick silvery scale, often at the elbows, knees and scalp, and symmetrical.
Granuloma annulare: a raised flesh-coloured or pink ring that is not scaly and not itchy, usually on the backs of the hands and feet. See Granuloma annulare: a ring-shaped rash that is not ringworm
Seborrheic dermatitis: red rash with greasy scale beside the nose, on the eyebrows, behind the ears and on the scalp. It is not ring-shaped.
Candida skin infection: in skin folds, bright red, with small satellite spots around the edge, and it can involve the scrotum.
How Do Doctors Diagnose Ringworm?
A dermatologist diagnoses ringworm from how the rash looks together with a test to confirm the fungus, which can be done in the clinic and takes little time.
Skin scraping with KOH solution (potassium hydroxide 10–20%): scale is scraped from the edge of the rash, a drop of solution is added, and it is viewed under a microscope. Branching fungal threads (hyphae) can be seen within minutes. This is the most important test and should be done before any antifungal is applied, because medicine applied earlier can stop the fungus from being found.
Fungal culture: used for scalp ringworm, nails, or cases that do not respond to treatment. It takes 2–4 weeks and identifies the species so that tablets can be chosen more precisely.
Wood’s lamp: helps only with certain scalp fungi that glow green. A negative result does not mean it is not ringworm.
Biopsy: rarely used, only when the rash does not fit the pattern or another disease is suspected.
What to Put on Ringworm: Topical Antifungal Groups
Ringworm in one or a few spots on the skin (body, groin, feet, face) is treated mainly with creams. The medicines used in medical practice are listed below (generic names only).
Group 1: Azoles
These medicines kill the fungi of ringworm, tinea versicolor and Candida, so they suit cases where you are not sure which fungus is involved.
Clotrimazole 1% cream: apply twice a day for 2–4 weeks (4 weeks on the feet).
Miconazole 2% cream: apply twice a day for 2–4 weeks.
Ketoconazole 2% cream: apply once or twice a day for 2–4 weeks.
Econazole 1% / isoconazole 1%: can be used interchangeably in the same way.
Group 2: Allylamines
These medicines kill dermatophyte fungi more strongly, so the course is shorter.
Terbinafine 1% cream: apply once or twice a day for 1–2 weeks on the body and groin, and 1–2 weeks between the toes (the moccasin type may need longer).
Naftifine 1%: once a day for 2 weeks.
Limitation: less effective than the azole group against Candida and tinea versicolor.
Group 3: Other Topicals and Forms of Medicine
Whitfield’s ointment (benzoic acid 6% + salicylic acid 3%): cheap and helps peel off thick scale on the soles. Apply twice a day for 4 weeks or more, but it irritates and stings, so do not use it in the groin, on the face or on broken, soggy skin.
Ciclopirox 1% and amorolfine: used on some skin types and on nails, as directed by a doctor.
Forms of medicine: dry, thick skin uses cream or ointment; wet, soggy skin or skin folds use a thin layer of cream or a powder. Medicated shampoo with ketoconazole 2% or selenium sulfide 2.5% is used as an extra in scalp ringworm to reduce spread (it is not the main treatment).
For a detailed comparison of each group of topical, read Antifungal creams: which one to choose and for how many weeks
5 Mistakes People Often Make When Applying Ringworm Cream
The right medicine applied the wrong way is the most common reason for “I used it and it did not clear”.
Wash and dry completely before applying, especially between the toes and in the groin. Leftover dampness lets the fungus grow faster than the medicine can kill it.
Apply 2 cm beyond the edge of the rash, because fungus that is still spreading is present on skin that looks normal around the border.
Apply the full number of times a day that the medicine requires. Applying every other day or only when it itches does not kill the fungus.
Keep applying for another 1–2 weeks after the rash has cleared. The rash fades before the fungus is dead. Stopping the moment the rash fades is the number one reason for recurrence.
Treat the source at the same time. For jock itch, treat the feet as well; if there is nail fungus, treat the nails; and if a pet has patchy hair loss, take it to a vet.
When Do You Need Tablets? Oral Treatment for Ringworm, Doses and Duration
Tablets are needed in 4 situations: (1) all scalp ringworm, (2) nail fungus, (3) a wide rash in several places, or chronic moccasin-type disease, and (4) no response to correctly applied cream, or low immunity. The doses below are those commonly used in adults. The actual medicine, dose and duration must be set by a doctor, who needs to consider your other conditions and the other medicines you take.
Terbinafine 250 mg once a day: widespread skin ringworm 2–4 weeks · fingernails 6 weeks · toenails 12 weeks · scalp ringworm in children, dose adjusted to body weight, for 4–6 weeks
Itraconazole 100–200 mg once a day: skin ringworm 1–2 weeks (or longer for resistant fungus). It should be taken with food and interacts with many types of medicine, such as some cholesterol medicines, heart medicines and some anti-seizure medicines.
Griseofulvin: long used for scalp ringworm in children, at 20–25 mg/kg/day (microsize) for 6–8 weeks, taken with a fatty meal for better absorption. It works especially well against Microsporum from cats.
Fluconazole 150–300 mg once a week: an option in some people, for 2–6 weeks.
Safety of oral medicine: a doctor may check liver tests before starting in people who need long courses or who have liver disease. Stop the medicine and see a doctor straight away if you have yellow skin or eyes, dark urine, severe nausea or a severe allergic rash, and oral medicine should not be used in pregnancy, when an azole cream such as clotrimazole is usually used instead.
Why Does Ringworm Spread After Steroid Cream? (Tinea Incognito)
An itchy red ring is often mistaken for an allergic rash, and people buy an anti-itch cream containing a steroid, or use a “combination” cream that puts an antifungal, an antibacterial and a steroid in one tube.
It looks better at first: the steroid reduces inflammation, the redness lessens and the itch drops within a few days.
But the fungus grows faster: the steroid suppresses local immunity, so the fungus spreads wider. The edge of the ring disappears, the rash becomes a shapeless red sheet with small pustules, and even a doctor cannot tell it is ringworm by looking. This is called tinea incognito (disguised ringworm).
Long-term effects: long use of a strong steroid in the groin or on the face thins the skin, causes stretch marks and widens small blood vessels, and it is an important factor behind chronic drug-resistant ringworm in South and Southeast Asia.
What to do: stop any steroid-containing cream and have a doctor take a scraping to confirm the fungus. If you have just stopped, the rash may get redder for a short time in the first 3–7 days, which does not mean the newly started antifungal is not working.
Ringworm That Will Not Clear, and Drug-Resistant Ringworm (Trichophyton indotineae)
If you have applied an antifungal correctly for a full 2–4 weeks and it has not improved, think of the causes in this order.
It was not ringworm in the first place, for example eczema or psoriasis. A scraping is needed to confirm.
The medicine was applied incorrectly or stopped too early, as in the 5 points above.
A hidden source of fungus, such as the feet, nails, someone at home or a pet.
The rash is too widespread for a cream to be enough, so tablets need to be added.
Resistant fungus. In recent years Trichophyton indotineae (formerly called T. mentagrophytes genotype VIII) has been reported. It began spreading from India and has been found in many countries, including Southeast Asia. It causes a wide rash in several places at once, with severe itching, spreads easily within families, and is often resistant to terbinafine because of SQLE gene mutations.
Resistant ringworm needs a dermatologist’s care. A fungal culture is often needed, with oral itraconazole for longer than usual (often 4–8 weeks or more), together with a cream and treatment of affected household members. Adding medicines on your own or switching creams over and over does not help and can make the fungus harder to detect.
How Many Days Does Ringworm Take to Clear? A Realistic Timeline
When the right medicine is used the right way, skin ringworm usually follows this pattern.
Days 3–7: the itch clearly lessens and the edge of the rash starts to look less red.
Weeks 2–4: the rash fades until it is almost invisible (terbinafine is usually faster than the azoles).
Keep applying for 1–2 weeks after it clears: to kill the remaining fungus. The total time for ringworm on the body is usually about 3–6 weeks.
Dark or red marks afterwards: these may last another 1–3 months, especially in people with darker skin. They are marks left after inflammation, not fungus that is still alive.
Moccasin-type athlete’s foot, scalp ringworm and nails: these take much longer. Scalp about 6–8 weeks, fingernails about 6 months before a new nail grows in, and toenails 12–18 months.
Signs that you should go back to a doctor: no improvement at all after 2 full weeks of correct treatment, or the rash spreads wider while you are applying the medicine.
Signs You Should See a Dermatologist
Scalp ringworm, patchy hair loss, or a swollen lump with pus
Nail ringworm, or a one-sided peeling palm that has lasted a long time
A wide rash in several places, or several people at home affected at the same time
No improvement after 2 weeks of correctly applied antifungal, or repeated recurrences
You have used steroid cream or a combination cream and the rash has changed or spread wider
You have diabetes, take immunosuppressive medicine, are having chemotherapy, or have HIV
You are pregnant or breastfeeding, or the patient is a child younger than 2 years
The rash is swollen, red, hot, very painful, has pus, or you have a fever, which may mean a bacterial infection has set in
How to Prevent Ringworm from Coming Back
Dry yourself in order: dry the groin and body first and the feet last, or use a separate towel for the feet.
Put socks on before underwear so that fungus from the feet is not carried to the groin.
Do not share towels, combs, hats or shoes with others. Wash towels, pillowcases and underwear in water at least 60 degrees Celsius, or dry them fully in strong sunlight.
Change out of sweaty clothes straight away after exercise, and choose fabrics that let sweat escape.
Wear sandals in communal showers and around swimming pools. Rotate at least 2 pairs of closed shoes so they have time to dry.
Check your pets: if a cat or dog has patchy hair loss or scale, take it to a vet and clean its bedding.
Check people at home: if several people have ringworm they must be treated at the same time, otherwise the fungus passes back and forth.
Do not put steroid cream on a rash when you do not know what it is.
For an overview of other common skin conditions, see Skin Conditions
Quick Summary
Ringworm (tinea) is a dermatophyte infection of the skin, hair and nails. The rash is a red ring with a raised, scaly edge, a paler centre, and itching.
Ringworm differs from tinea versicolor: tinea versicolor is caused by Malassezia yeast, forms small spots with fine powdery scale, itches little, and is far less contagious.
Ringworm in one or a few spots on the skin is treated with clotrimazole 1%, miconazole 2% or ketoconazole 2% cream for 2–4 weeks, or terbinafine 1% for 1–2 weeks. Apply 2 cm past the edge and keep going for another 1–2 weeks after the rash clears.
Scalp ringworm, nail fungus and wide rashes need tablets prescribed by a doctor. A cream alone is not enough.
Do not put steroid cream or combination cream on it yourself, because it makes ringworm spread and harder to diagnose.
If there is no improvement after 2 weeks of correct use, see a dermatologist for a scraping and a check for resistant fungus.
Frequently Asked Questions About Ringworm
How does ringworm differ from tinea versicolor?
Ringworm is caused by dermatophyte fungi and spreads from people, pets or soil. The rash is a red ring with a clearly raised edge, scale along the border, a paler centre, and clear itching. Tinea versicolor is caused by Malassezia yeast, which already lives on everyone’s skin. The rash is made of small spots 3–5 millimetres across, white, pink or light brown, with fine powdery scale, usually on the back, chest and shoulders, with little itching, and it is hardly contagious. Azole creams can be used for both diseases, but oral terbinafine works only for ringworm and does not work for tinea versicolor. If you are not sure, a dermatologist can tell them apart within minutes with a skin scraping and KOH solution.
How many days does ringworm take to clear?
For ringworm on the body, arms, legs and groin, when the right cream is used the right way, the itch usually improves within 3–7 days and the rash fades in 2–4 weeks. You then need to keep applying for another 1–2 weeks after the rash has cleared, about 3–6 weeks in total. Terbinafine cream usually takes less time than the azole creams. Scalp ringworm needs tablets for about 6–8 weeks, and nail fungus takes several months before a new nail grows in. If there is no improvement at all after 2 weeks of correct use, see a doctor, because it may not be ringworm or it may be resistant fungus.
Does ringworm go away on its own?
Most ringworm does not go away by itself, or if it seems to settle it usually comes back, because the fungus is still living in the outer skin and keeps spreading outward. It can continue for months or even years, and during that time it can still spread to people at home, to pets and to other parts of your own body, especially from the feet to the groin and hands. Treating with an antifungal while the rash is still small takes less time and works better. Scalp ringworm in children should not be left to see what happens, because an inflamed, pus-filled lump can leave scarring that causes permanent hair loss.
How do I get rid of ringworm?
Do 4 things together. One, use an antifungal from the right group, such as clotrimazole or ketoconazole once or twice a day for 2–4 weeks, or terbinafine 1% for 1–2 weeks. Two, apply it about 2 centimetres beyond the edge of the rash and keep going for another 1–2 weeks after the rash clears. Three, treat the sources of infection, such as the feet, nails, people at home and pets. Four, keep the skin dry, do not share towels, and stop any steroid-containing cream. If it is on the scalp or nails, or a wide rash in several places, a doctor needs to prescribe tablets as well.
Which medicine clears ringworm fastest?
For ringworm in one spot on the skin, terbinafine 1% cream takes the least time, about 1–2 weeks, because it kills dermatophyte fungi directly. Azole creams such as clotrimazole 1% or ketoconazole 2% usually need 2–4 weeks but cover a wider range of organisms, so they suit cases where you are not sure whether it is ringworm, tinea versicolor or Candida. How fast it works depends more on applying it correctly than on the medicine, and the “fastest medicine” for scalp ringworm, nails or a wide rash is the tablet a doctor prescribes, not a stronger cream.
Can I treat ringworm myself?
Ringworm in one or a few spots on the skin of a healthy adult can usually be started with a single antifungal cream, as long as it contains no steroid, is applied past the edge of the rash and is continued after the rash clears. See a dermatologist instead of treating it yourself if it is on the scalp, face, nails or palms, if it is a wide rash in several places, if you have used steroid cream before, if you have diabetes or low immunity, if you are pregnant or the patient is a small child, and if it has not improved after 2 weeks of correct use. Many diseases cause round rashes that look like ringworm, and resistant fungus needs a culture and a long course of tablets.
Written by Dr. Patara Voravutinon, Dermatologist · Last reviewed October 5, 2026
The information in this article is general knowledge and is not a diagnosis or a personal prescription. The choice of medicine, dose and duration of treatment should be assessed by a doctor.
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