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.
Key facts
Ringworm at a glance.
Typical signs
Ring-shaped rash with scaly edges
Common locations
Body, groin, feet or scalp
Expected course
Clears with antifungals
Treatment options
Antifungal cream; pills for scalp infection
What is it?
Top things to know about Ringworm
- It is a fungal skin infection. Tinea corporis is dermatophyte infection of body skin.
- The ring is a clue only. It may be absent, especially after steroid creams.
- It is an umbrella term. Related infections affect the scalp, nails and other sites.
- Testing guides treatment. Scrapings or culture confirm infection; scalp and nail infections need different care.
What it looks like
What Ringworm looks like
Ringworm is a fungal skin infection, not a worm. On the body, it usually forms a round or oval patch with a scaly, raised edge that slowly spreads outward while the center clears, creating a ring shape. It often itches. Several rings can appear and join. It spreads by contact with infected people, pets, especially cats, and contaminated surfaces.
Ringworm is named by where on the body it grows. Each type has its own common name.
Tinea corporis (body ringworm)
Rings on the body and limbs.
Tinea capitis (scalp ringworm)
Generated illustration. Scaly patches with hair loss.
Tinea cruris (jock itch)
Jock itch in the inner thighs.
Tinea pedis (athlete’s foot)
Athlete's foot.
Where it shows up
Ringworm can occur at many skin sites. The shaded trunk patch is one location example, not a characteristic body-wide distribution.
Trunk
Locations on the front of the trunk.
On different skin tones
Ringworm on different skin tones
On lighter skin, ringworm rings look pink to red. On brown and Black skin, they are often brown, gray or darker than the surrounding skin. Scalp ringworm is especially common in Black children and can look like dandruff, patchy hair loss or swollen tender bumps.
What happens in Ringworm?
Dermatophyte fungi grow in the keratin of the outer skin and spread outward. Inflammation and scale often concentrate at an expanding border, while the center may look clearer.
- Fungi grow in outer keratin: Dermatophytes affect the surface layer.
- The active edge expands: Inflammation and scale often mark the border.
- The center may look clearer: An enlarging ring can develop.
Causes and triggers
What causes Ringworm
Causes
Why it happens
Ringworm is a fungal infection of the skin's outer layer. It isn't caused by a worm; the name comes from the ring-shaped rash.
Risk factors
Raise the odds
- Children
- Contact sports
- Weakened immunity
- Diabetes
Triggers
Passes it on
- Skin-to-skin contact (Well established)
- Infected pets, especially cats (Well established)
- Shared towels, combs and mats (Strong link)
- Damp, warm skin (Strong link)
When it usually starts
When it usually starts
Ringworm
Can occur at any age after exposure to an infected person, animal or contaminated material.
Daily care
Daily care for Ringworm
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.
Shower and change soon after sport
The single best habit if you train.
Keep the area dry
Dry thoroughly, change sweaty clothes, wear loose cotton.
Treat the feet and nails too
Otherwise they reseed it.
An over-the-counter antifungal cream
Terbinafine, clotrimazole, miconazole, ketoconazole.
Apply the antifungal over the recommended margin and complete the labeled course
Cover the affected area and the margin directed on the label. Duration differs between products and sites.
Avoid: Sharing household items
Towels, bedding, clothes or hairbrushes pass it on.
Avoid: Walking barefoot
Communal showers and pool areas are a classic route.
Avoid: Contact sport before it is treated
Very transmissible skin to skin.
Avoid: Staying in damp clothes
Fungi need moisture. The easiest thing here to fix.
Avoid: Tight, occlusive clothing over the patch
Traps heat and sweat over the fungus.
Avoid: Scratching
Breaks the skin and carries fungus to new sites.
Avoid: Not treating the pet
If an animal is the source, treating only people means it returns.
Avoid: Untreated athlete's foot or nail fungus
A permanent source for the body.
Avoid: Stopping treatment when it looks clear
Skin clears before the fungus does.
Avoid: Hydrocortisone 1%
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.
Avoid: Steroid–antifungal combinations
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.
Treatments
Treatments for Ringworm
Terbinafine cream
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
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
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.
Tea Tree Oil
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.
Ketoconazole
Ketoconazole 2% cream. 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.
Ciclopirox
Ciclopirox cream. 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.
Econazole
Econazole cream. 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.
Terbinafine
Terbinafine tablets. 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.
Itraconazole
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.
Griseofulvin
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.
Fluconazole
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.
Outlook
What to expect with Ringworm
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.
- 1
Days 4 to 14 after contact · Starting
A small itchy pink, brown or gray spot where the fungus landed. Easy to miss.
- 2
Weeks 1 to 3 · Spreading
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.
- 3
Days 2 to 7 of treatment · Settling
With an antifungal cream the itch improves within a few days and the border starts to flatten.
- 4
Weeks 2 to 6 of treatment · Clearing and finishing
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.
- 5
After clearing · Marks
A flat pale or dark mark can stay for weeks to months, especially on deeper skin tones. Not active infection.
Complications
Complications to know about
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
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.
When to get help
When to get help
When to seek care
Seek care for widespread, recurrent or uncertain rash, or scalp involvement. Steroid cream alone can disguise and worsen a fungal infection.
Lookalikes
What else could it be?
Eczema
Ringworm usually has a raised, scaly rim and a clearer center. Eczema’s edges tend to be softer, with scale spread across the patch.
Psoriasis
Psoriasis often forms thicker patches in matching places on both sides. Ringworm more often spreads outward from one ring-shaped patch with a clearer center.
Contact Dermatitis
Contact dermatitis matches where something touched the skin and lacks an advancing rim. Ringworm keeps growing outward from a raised, scaly edge.
Questions
Questions you might be asking.
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.
Sources
Sources and further reading
Related
Keep exploring.
Contact Dermatitis
Eczema
Psoriasis
Terbinafine
Fluconazole
Ketoconazole
Tea Tree Oil
Contact Dermatitis vs Ringworm
Eczema vs Ringworm
Psoriasis vs Ringworm
Ringworm vs Tinea Versicolor
