Ringworm

Ringworm is one of the most common skin infections that Dr Glass treats from his offices in London. Despite the alarming name, no worms are involved. The infection, also known as tinea or dermatophytosis, is caused by fungi called dermatophytes, which thrive on the outer layer of the skin. Around 40 different species of dermatophytes can cause ringworm, and the infection can appear almost anywhere on the body.

Ringworm goes by different names depending on where it appears. Athlete's foot (tinea pedis) is ringworm of the foot, jock itch (tinea cruris) is ringworm of the groin, tinea capitis affects the scalp, and tinea corporis refers to ringworm on the body. Whatever the location, the underlying cause is the same fungal infection, and the good news is that it responds well to treatment once correctly diagnosed.

What does ringworm look like?

The classic sign of ringworm is a circular or ring-shaped rash with a raised, scaly edge and a clearer centre. On lighter skin the rash usually appears red or pink; on brown and black skin it may look grey, brown or darker than the surrounding skin, which can make it harder to spot. The patch is often itchy, dry or flaky, and it may slowly grow outwards or multiply into several patches.

Not every ringworm infection follows this textbook pattern. On the face, neck or scalp the rash may not form an obvious ring at all. Scalp ringworm can cause scaly patches, broken hairs and patchy hair loss, while athlete's foot typically causes white, soggy, peeling skin between the toes. Fungal nail infections cause nails to become thickened, discoloured and brittle.

It is also worth knowing that not every circular rash is ringworm. Conditions such as eczema, psoriasis and pityriasis rosea can look remarkably similar, which is one reason an accurate diagnosis matters before starting treatment.

Ringworm or skin cancer? When to be concerned

Because ringworm can be scaly and slow to change, people sometimes worry that a patch might be something more serious, such as a melanoma or another skin cancer. Reassuringly, the two look quite different. Ringworm is a fungal infection that typically forms a red, pink or brown ring with a raised, scaly border and a clearer centre, is usually itchy, and spreads outwards over days to weeks. A melanoma is not an itchy ring; it usually develops from a new or changing mole and shows the warning signs summed up by the ABCDE rule: Asymmetry, an irregular Border, more than one Colour, a Diameter larger than about 6mm, and Evolving or changing over time.

The most useful practical difference is how they respond to treatment. Ringworm clears with antifungal cream within a couple of weeks, whereas a suspicious mole or skin-cancer lesion will not. If a patch does not settle with antifungal treatment, keeps changing, bleeds, crusts or will not heal, it should be assessed properly rather than treated as ringworm. Whenever there is any doubt, Dr Glass can examine the area and, if needed, arrange skin cancer checks or a biopsy to be certain.

How do you get ringworm?

Ringworm is contagious and can be passed from one infected person to another, normally through close skin-to-skin contact. Sharing belongings with an infected person, such as towels, bedding, clothing, combs or hairbrushes, also raises your risk of catching it. The fungi can survive on these surfaces for some time, which is why the infection spreads easily within households, schools and gyms.

You can also get ringworm from pets. Cats, dogs and other animals can carry the infection, sometimes with visible patches of missing fur and sometimes with no obvious signs at all. Less commonly, the fungi can be picked up from contaminated soil.

Anyone can develop ringworm, but some people are more susceptible than others. Children are particularly prone to scalp ringworm, while athlete's foot and jock itch are more common in adults who exercise regularly, wear tight footwear or spend time in communal changing rooms and swimming pools. Warm, moist skin gives the fungus ideal conditions to grow, and people with weakened immune systems, for example from diabetes, chemotherapy or long-term steroid use, are at higher risk of stubborn or widespread infection.

How is ringworm diagnosed?

Doctors trained in dealing with skin infections can examine a patient's skin and make an initial diagnosis, as the appearance of the rash usually reveals the nature of the infection right away. Because several other skin conditions can mimic ringworm, however, an experienced eye makes a real difference.

In some instances, the skin is gently scraped and the sample sent to a laboratory, where it is examined under a microscope and cultured to try to grow the fungus causing the ringworm. This confirms the diagnosis and can identify the exact species involved, which is particularly useful for scalp and nail infections or when a previous treatment has not worked. For suspected fungal nail infections, nail clippings can be tested in the same way.

Ringworm treatment options

Often people with ringworm do not seek medical attention and simply treat themselves. For small, uncomplicated patches on the body, that is a reasonable first step. Antifungal creams, gels and sprays can be bought over the counter from any pharmacy, and most mild infections clear within two to four weeks of consistent use. It is important to keep applying the treatment for the full recommended course, even once the rash appears to have gone, because stopping early is a common reason infections return.

Sometimes ringworm is difficult to diagnose or fails to respond, and help from a dermatologist should be sought. Some fungal infections do not respond well to over-the-counter creams and require professional care. You should consult a dermatologist when skin lesions do not improve with self-care, when the infection keeps coming back, or when the rash is widespread. Cases of extensive fungal infection need to be assessed and treated by a physician, and stronger prescription medications, some of which need to be taken orally, may be required.

Scalp ringworm needs specialist treatment

Ringworm on the scalp should always be seen by a dermatologist. Antifungal creams are not effective enough on their own for scalp infections, because the fungus penetrates the hair shafts where creams cannot reach. Physicians address tinea capitis with prescription antifungal medication taken orally, usually for one to three months. Commonly prescribed medications include griseofulvin, terbinafine, itraconazole and fluconazole, often alongside an antifungal shampoo to reduce spread to others. Treating scalp ringworm promptly matters, because untreated infections can lead to scarring and permanent hair loss in severe cases.

Fungal nail infections

Fungal infections of the nails also tend not to respond well to creams. Once the diagnosis is confirmed, nail infections generally need treatment with oral antifungal medication, and treatment courses are longer than for skin infections because nails grow slowly. A dermatologist can confirm the diagnosis first, since not every discoloured or damaged nail is fungal, and taking months of antifungal tablets for the wrong condition helps nobody.

How to stop ringworm spreading

Alongside treatment, a few practical habits will protect the people around you and stop the infection travelling to other parts of your own body. Wash towels, bedding and clothes regularly and avoid sharing them while the infection is active. Keep the affected skin clean and dry, wash your hands after touching the rash, and try not to scratch it, as scratching can transfer the fungus to other areas. Dry carefully between your toes after showering, and wear flip-flops in communal changing rooms and pool areas. If you suspect a pet is the source, a trip to the vet is worthwhile, as animals need treating too or the infection will simply pass back and forth.

There is no need to stay off work or school once treatment has started.

Frequently asked questions about ringworm

Is ringworm caused by a worm?

No. Ringworm is caused by dermatophyte fungi. The name comes from the ring-shaped rash the infection often produces.

How can I tell ringworm from skin cancer?

Ringworm is usually an itchy, scaly ring that spreads outwards and clears with antifungal cream within a couple of weeks. Skin cancers such as melanoma tend to arise from a new or changing mole, are not itchy rings, and do not respond to antifungal treatment. Any patch that keeps changing, bleeds or will not heal should be checked by a dermatologist.

How long does ringworm take to clear up?

Mild skin infections usually clear within two to four weeks of antifungal cream. Scalp infections typically need one to three months of oral medication, and nail infections can take longer still.

Is ringworm contagious?

Yes. It spreads through skin contact with an infected person or animal and through shared items such as towels, bedding and hairbrushes. Starting treatment quickly reduces the risk of passing it on.

When should I see a dermatologist about ringworm?

See a dermatologist if the rash has not improved after two weeks of over-the-counter treatment, if it keeps returning, if it is widespread, or if the infection affects your scalp or nails. People with weakened immune systems should also seek professional care rather than self-treating.

Concerned you may have ringworm?

Most ringworm infections are straightforward to treat, but the right diagnosis is the essential first step, particularly for scalp, nail and recurrent infections. If you are concerned you may have ringworm or another skin condition, please call 020 3282 0011 or email info@danielglass.co.uk to book an appointment with Dr Glass today.

This article is for general information and is not a substitute for a professional medical assessment. If you are worried about a rash or skin change, please seek advice from a qualified dermatologist.