Ringworm, or tinea, refers to several types of contagious fungal infections of the top layer of the skin, scalp, and nails.
It is called ringworm because the itchy, red rash has a ring-like appearance. Ringworm is nothing to do with worms.
In this article, we will cover ringworm's diagnosis, causes, symptoms, and treatment.
Contents of this article:
Fast facts on ringworm
Here are some key points about ringworm. More detail and supporting information is in the main article.
- Ringworm is nothing to do with worms
- Ringworm is caused by a fungus that eats keratin in skin and nails
- Children under 15 are particularly susceptible to ringworm
Types of ringworm
Ringworm is classified according to which part of the body is affected:
- Scalp ringworm (tinea capitis) - most common in younger children. Adults can be affected, but that is rare. Scalp ringworm is more common in urban environments because people are closer together, giving the fungus more opportunities to spread.
- Body (skin) ringworm (tinea corporis) - this can affect babies, children, and adults.
- Groin infections (tinea cruris) - also known as jock itch. More common among young men.
Causes of ringworm
Ringworm is caused by a fungus that eats keratin.
Ringworm is caused by a type of fungi that eat keratin, called dermatophytes.
Dermatophytes attack the skin, scalp, hair, and nails because those are the only parts of the body with enough keratin to attract them.
Dermatophytes are microscopic spores which can survive on the surface of the skin for months. They can survive equally well in towels, combs, the soil, and other household objects - they are incredibly resilient.
Dermatophyte spores spread in the following ways:
- Object-to-human - infected people and animals may deposit fungal spores on objects and surfaces when they touch them; anyone who touches those objects may become infected
Although children invariably show symptoms when they become infected, many adults don't. The older an individual is, the more likely their immune system will protect them - but they may still be a carrier.
Risk factors for ringworm
The following risk factors either increase your chances of developing ringworm, or make the symptoms worse:
- Age - children younger than 15
- Weakened immune systems - patients with HIV/AIDS are more likely to get ringworm
- Medications that lower the immune system
- Living in warm, humid climates
- Being close to infected people or animals
- Sharing clothing or towels with infected people
- Hyperhidrosis - a condition where the individual sweats more than usual
- Contact sports - sports where human-to-human contact is the main part of the activity, for instance, wrestling
- Tight clothing - tight clothing restricts ventilation, making conditions ideal for the fungus to thrive
Symptoms of ringworm
Symptoms vary depending on the type of ringworm:
Symptoms of scalp ringworm
- Small patches of scaly skin appear on the scalp
- Patches may feel tender or painful and be inflamed
- Hair on or near the patches breaks away
- Kerion - large inflamed sores form on the scalp which may ooze pus
- The patient may have a temperature and swollen glands (lymph nodes), but this is uncommon
Symptoms of body (skin) ringworm
- Rash - with a ring-like appearance. The skin may be red and inflamed around the outside of the ring, but look fine in the middle.
- Merging rings - when there are enough of them, they will merge together.
- Rings feel slightly raised.
- Itchiness - especially under the rash.
Symptoms of a groin infection
- Itchiness - especially in and around the groin
- Redness - the affected area becomes red, and may feel like burning
- Inner thighs - skin may become flaky and scaly
- Walking, running, or exercising worsens symptoms
- Tight clothing makes symptoms worse
Diagnosing ring worm
Diagnosis of ringworm can often be made from a visual examination.
A doctor should be able to diagnose ringworm or groin infection after examining the affected area and asking the patient about their medical history and symptoms.
In some cases, the doctor may take a small scraping of the skin (which will not hurt) and examine it under a microscope to look for characteristics of fungi.
The doctor will assess whether the skin problem is being caused by some other disorder, such as psoriasis. Further testing is not usually needed unless symptoms are particularly severe.
If symptoms have not improved after treatment, the doctor may remove a small piece of infected skin and send it to the lab to be analyzed.
Treatment for ringworm
Treatment depends on the type of ringworm:
Scalp ringworm treatment
The most common treatments for scalp ringworm are oral antifungals (tablets). However, the choice of medication will depend on the type of fungi involved.
Terbinafine (Lamisil) - side effects are normally mild and do not last long; they may include diarrhea and nausea. People with a history of liver disease should not take terbinafine.
Anti-fungal shampoos - help prevent the spread of ringworm and may speed up recovery, but they do not cure it.
Shaving a child's head - there is no evidence that this reduces ringworm infection, or accelerates recovery time.
Skin ringworm and groin infections treatment
The majority of cases are treated with OTC anti-fungal creams. Individuals should read instructions carefully - anti-fungal creams do not all have the same instructions.
If symptoms are severe, or if they cover a large area of the body and do not respond to OTC medications, the doctor may prescribe a prescription-strength topical medication.
The doctor may prescribe an oral medication (taken by mouth). Oral medications can have some side effects, including stomach upset, rash, or abnormal liver function.
Caring for the skin during infection
- Wash skin gently.
- Dry skin thoroughly, but gently. Pat skin with a towel in tender areas, don't rub. Make sure folds and areas between the toes are dried thoroughly.
- Change underwear more often than usual (groin infection)
- Athlete's foot and groin infection - always treat both areas at the same time. Groin infections are often caused by infection that started with athlete's foot, and sometimes vice-versa.
- Wear loose-fitting clothing as much as possible.
Prevention of ringworm
If somebody has ringworm in the house:
- Pets - if the pet is the source of the infection, it will need to be taken to the vet
- Wash hands regularly with antibacterial and antifungal soap, or one that contains tea tree oil
- Everyone in the house should check themselves for signs of ringworm
- Do not share combs, hairbrushes, clothing, bed linen, towels, or footwear
- Do not scratch affected areas as this increases the risk of spreading the infection
- Clothing - wear light, loose clothing, especially if the weather is warm
- Try to avoid excessive sweating
- Avoid walking around the house with bare feet
- Wash clothes in hot water with fungicidal soap
Complications of ringworm
Fungal infections rarely spread below the surface of the skin. The risk of any serious illness is very small. If complications do occur, they may include:
- Spreading - the infection may spread from one part of the body to another.
- Bacterial infections - if the skin is broken, bacteria may get in and cause an infection.
- Weakened immune systems - people with HIV and other conditions that weaken the immune system are much more likely to experience spreading of ringworm. It is more difficult to get rid of the infection if the immune system is weak.