Ringworm is a skin infection that is caused by over 40 different fungi. It is, therefore, not caused by a worm but takes its name from the ring-shaped rash it causes.

It is not a serious or life-threatening health condition and can be successfully treated. However, it is highly contagious.

Here, we will explore how ringworm infection spreads, its symptoms and treatments, as well as how to reduce your risk of developing ringworm.

Types of ringworm

Ringworm, which is also known as tinea, can affect any area of your skin, including your scalp and your nails. The different types of ringworm can, therefore, be grouped according to the specific areas of the body they affect.

One of the most common types of ringworm is athlete’s foot, also known as tinea pedis. This can affect any part of your foot but most commonly develops on the skin between the toes. It can spread to the nails of your feet where it causes tinea unguium or onychomycosis.

Tinea unguium is a fungal nail infection and can affect both your toenails and fingernails. When ringworm affects your hands, it is called tinea manuum.

Ringworm that develops on your scalp is called tinea capitis while ringworm that affects your groin area is called tinea cruris or jock itch.

Ringworm that affects any other part of your body, such as your arms, legs, trunk and buttocks, is called tinea corpis.

Symptoms of ringworm

Ringworm usually — but not always — causes a ring-shaped rash and dry, scaly, itchy skin. It can take several days after infection for the rash to appear, which often starts as tiny red bumps. These bumps then spread to form rings that are 1.5 to 2.5cm in diameter.

The skin inside the rings can either appear normal or have bumps that are similar in colour to the ring-shaped part of the rash. On fair skin, rings and bumps appear red, while on darker skin they can appear purple, grey, silver or darker brown.

On the hands, the ring-shaped rash develops on the backs of the hands and the palms become dry and cracked.

On the scalp, however, the rash may not be ring-shaped but rather form flaky, scaly patches. These patches can take up to 2 weeks after infection to appear. In more severe cases, the patches of red, itchy, inflamed skin can cause the hair in this area to fall out.

As on the scalp, patches of rash tend to form in the groin area rather than rings.

Infection of the nails also doesn’t cause a ring-shaped rash. Instead, nails become yellowed, thickened and brittle, and peel away from the nail bed (the skin that your nail sits on top of). This makes them more prone to breaking.

In severe cases, pustules (pus-filled blisters or pimples) can develop and rings may grow larger and merge with each other.

Conditions mistaken for ringworm

Several conditions can be mistaken for ringworm due to overlapping symptoms.

For example, eczema can cause dry, itchy skin that is inflamed and red. However, the rash that develops with eczema is not ring-shaped. Unlike ringworm, eczema is not caused by a fungal infection and is not contagious.

Similarly, psoriasis can cause dry, itchy, red and inflamed skin with silvery, grey scales. But it does not produce a ring-shaped rash, is not caused by a fungal infection and is not contagious.

The skin condition granuloma annulare, however, does cause a ring-shaped rash but the rash is not itchy or scaly. Its cause is unknown and it is not contagious.

Lyme disease, which is caused by bites from black-legged ticks, can also produce an itchy, ring-shaped rash, which forms around the bite site. The rash spreads out from this site and is accompanied by other symptoms of Lyme disease, such as fever, muscle and joint pain, fatigue and headaches.

Pityriasis rosea can also initially cause a single ring-shaped rash, usually on the trunk of your body. However, after this initial ring, the rash develops into smaller red spots. It is likely triggered by a viral infection but is not itself contagious.

When ringworm affects the scalp, the scaly and flakey skin may resemble dandruff.

How ringworm spreads

As ringworm is caused by fungi, warm, damp environments are ideal places for ringworm to spread eg around swimming pools and in public showers.

You can become infected with ringworm if you are in close contact with an infected individual or animal, or if you come into contact with towels, combs, bedding or clothes used by an infected individual.

In very rare cases, ringworm can be contracted from highly infected soil.

Risk factors for ringworm

While ringworm is often associated with children, it can infect anyone of any age.

However, you are more likely to become infected if you have a weakened immune system (eg if you have HIV or AIDs, or are having chemotherapy), diabetes, hyperhidrosis (excessive sweating), or are obese or overweight.

Your risk is also higher if you take part in sports with skin-to-skin contact (eg wrestling or rugby), or use public showers, pools or changing rooms, especially if you are barefoot in these areas.

Wearing tight clothes that chafe your skin, living in warm, humid environments and having close contact with animals also increase your risk.

Getting a diagnosis of ringworm

If you think you have ringworm, which is not on your scalp, and you do not have a weakened immune system, see your local pharmacist. If you think you have ringworm on your scalp and/or you have a weakened immune system, see your GP.

They will usually be able to diagnose ringworm by looking at your skin.

Treatment for ringworm

Ringworm is most often treated with an over-the-counter antifungal medication. Depending on which part of your body is affected by ringworm, this may be taken orally as tablets or applied topically as a spray, cream or gel.

Antifungal medication for ringworm usually needs to be taken every day for up to 4 weeks. Make sure you follow the instructions of your pharmacist or GP and complete the treatment course. If you don’t complete your treatment, ringworm can recur.

With treatment, your symptoms should start to improve within 2 weeks and in most cases, your ringworm should be cured after 4 weeks.

The exception is ringworm on your scalp or nails, which can take several months to fully resolve. You may, therefore, need to remain on treatment for up to 3 months.

If you have ringworm on your scalp, you will need to take prescription antifungal tablets and use a prescription antifungal shampoo.

If you have ringworm that is not responding to over-the-counter antifungal medication after 2 weeks, see your GP. You may need to take a prescription antifungal medication.

Dos and don’ts if you have ringworm

Avoid scratching your rash as much as possible as this makes it more likely that you will spread it to other parts of your body that you touch.

To reduce the risk of spreading ringworm to others, you should avoid sharing clothes, combs, towels or bed linen with anyone else while you have ringworm. Make sure you wash these items and your hands regularly.

As the fungi that cause ringworm can survive on surfaces in warm, moist areas for months, it is important to disinfect surfaces with bleach or another disinfectant spray.

You should also start treatment as soon as possible and complete your course of treatment. Ringworm very rarely gets better on its own and the longer you delay treatment, the greater the chances of spreading it.

However, avoid using anti-itching creams that contain corticosteroids. Corticosteroids weaken the immune system where they are applied and, therefore, when applied on a ringworm rash can leave your skin more vulnerable to the infection. This makes it easier for the rash to spread.

Complications of ringworm

For most people, ringworm is not a serious health condition. It does not spread beyond the upper layers of the skin and resolves with treatment over several weeks or months.

However, if you have a weakened immune system, such as if you have HIV or AIDs, or are undergoing chemotherapy, ringworm can become more severe. The rash can spread further and persist for longer even with treatment.

How to prevent ringworm

To reduce your risk of contracting ringworm, make sure you do not walk barefoot in public spaces, particularly those that are damp, such as around pools, or in shower rooms and changing rooms.

Make sure you wash daily and dry yourself off thoroughly. This is especially important if you become sweaty or go swimming in public pools.

Wash towels, clothes (especially sports clothes, uniforms and hats) and bedding regularly, and do not share unwashed clothes, hats, linens, towels or combs. Change your clothes daily and avoid wearing clothes that chafe your skin.

You should also regularly wash your hands, especially after petting or handling animals. If you notice your pet is infected, take them to the vet to get treated as soon as possible. Signs of ringworm in cats and dogs include circular patches of hair loss, broken hair, scaly and/or inflamed skin, and excessive scratching,

Ringworm and pregnancy

Ringworm does not pose a risk to pregnancy. However, certain antifungal medications may not be safe to use during pregnancy. You should, therefore, speak to a pharmacist or GP to find out which creams, gels, sprays or tablets are safe for you to take.