Why ringworm keeps coming back, and why mixed creams from the chemist make it worse

It starts as a ring-shaped, itchy patch, often in the groin, at the waist or under the breasts. A cream from the chemist clears it in a week. Then it is back, a little larger, sometimes in a new place, and the same cream works less well each time.

If this sounds familiar, you are in very large company. Over the last decade dermatologists across India have described fungal skin infection that is more widespread, more stubborn and more likely to return than it used to be. This article explains why, what the mixed creams sold over the counter have to do with it, and what tends to work. It does not replace a visit to a dermatologist, and it does not tell you which medicine to take.

What ringworm actually is

Ringworm has nothing to do with worms. It is an infection of the outer layer of the skin by a group of fungi called dermatophytes, and doctors call it tinea, with a second word for where it is: tinea corporis on the body, tinea cruris in the groin, tinea pedis on the feet, tinea capitis on the scalp.

These fungi live on dead skin, hair and nails. They thrive where skin is warm, damp and covered: skin folds, under tight clothes, in sweaty socks. India’s heat and humidity give them an easy start, and close living spaces give them easy ways to move from one person to the next.

Why it has become harder to treat

Several things have come together.

Mixed creams sold over the counter. Many creams sold without a prescription in India combine three things in one tube: a steroid, an antifungal and an antibiotic. They are popular because they work fast. The steroid makes the itch and the redness settle within days. But it does nothing to the fungus. It does the opposite.

Stopping too early. A fungal rash looks better long before the fungus is gone. When treatment stops at that point, the infection returns from what is left.

Spread within the home. One person treats their rash, while a spouse, a child or a parent has an untreated patch, or the infection lives on in towels and bedding. The treated person catches it again.

A harder strain. Doctors have identified a species, Trichophyton indotineae, first described from patients in India and Nepal and now reported in many countries. Many of its strains respond poorly to some of the most widely used antifungal medicines. Infections caused by it can need tests, a different medicine and a longer course, which is a decision for a dermatologist.

What a steroid cream does to a fungal rash

This is the part most people do not expect.

A steroid reduces inflammation. Inflammation is the skin’s response to the fungus: the redness, the raised edge, the itch. When the steroid switches that response down, the rash looks better and itches less. Meanwhile the fungus, no longer held back, keeps growing.

Used for weeks, the result is often:

• a rash that is larger than it was, with blurred edges rather than a clear ring, which makes it harder for a doctor to recognise;
• infection in new places, where the cream was spread with the hands;
• thinning of the skin, visible blood vessels and stretch marks where the cream was applied, especially in the groin and on the inner thighs;
• a rash that flares when the cream is stopped, which keeps people using it.

If you have been using such a cream, do not be embarrassed to say so. It is one of the most useful things you can tell the doctor. Take the tube with you.

What happens at the dermatologist

A dermatologist will look at the rash, ask how long you have had it and what you have put on it, and often check other members of the household. They may scrape a little skin from the edge of the rash for a KOH test, a quick look under the microscope for fungus, and sometimes send a sample for culture to identify the species.

Treatment is chosen from what they find. For an infection that has come back several times, it may include tablets as well as a cream, and it usually continues for some time after the skin looks clear. Follow-up visits matter, because they are how the doctor decides when to stop.

Keep the prescriptions and the dates. If the rash returns a year later, the next doctor will want to know exactly what was used and for how long. A record on your phone, such as your 92health record, keeps every prescription and visit summary in one place, whichever clinic wrote it.

What helps at home, alongside treatment

These do not replace treatment, but they make it far more likely to work:

• Dry the skin well after bathing, especially in folds. Moisture is what the fungus needs.
• Wear loose, cotton clothing and change underwear and socks daily. Avoid tight synthetic fabrics in hot weather.
• Do not share towels, clothes, combs or bedding while anyone in the house has a rash.
• Wash clothes, towels and bedsheets used during the infection, and dry them fully, in the sun where possible.
• Make sure everyone in the house with a rash is treated at the same time.
• Keep nails short and try not to scratch, which spreads the fungus to new skin.

When not to wait

See a dermatologist rather than trying another cream if:

• the rash is spreading or covers a large area;
• it has come back after treatment;
• it is on the face, scalp or groin;
• you have been using a steroid or mixed cream;
• the person affected is a child, is pregnant, or has diabetes or a weakened immune system;
• the patch is painful, oozing or does not look like a ring.

Fungal skin infection is common and very treatable. It is also one of the conditions where the fastest-looking fix makes the problem last longest.