What Is Ringworm

Ringworm (also known as tinea or dermatophytosis), is a fairly common and contagious skin, nail and hair infection. Though it is called ringworm, it is not caused by a worm, but by a fungus, dermatophyte, causing itchy, circular red patches or lesions. It is possible to get ringworm from contact with infected people, objects and animals.¹

Types of ringworm infections

Dermatophytosis

Ringworm has various types depending on the area that is affected.² These include: 

• Tinea corporis (body ringworm) – causes red scaly patches in any part of the body, excluding the hands, feet, scalp, face and beard
• Tinea pedis (athlete's foot) – causes itchy, burning skin rash on the soles of the feet and in between the toes. The skin can appear scaly cracked and blistered too. Due to the fungal infection, your feet may smell bad too
• Tinea capitis (scalp ringworm) – causes red, scaly, bald spots on your scalp and if it is left untreated then the bald spots can increase in size and become permanent
• Tinea cruris (jock itch) – causes itchy, red in the groin, rectum or upper thighs. Blisters may also form
• Tinea unguium (nail ringworm) – nails become thick, deformed and discoloured

Non-dermatophyte fungal infections

Some other types of fungal infections include: 

• Tinea versicolor (skin) – causes small, and discoloured patches in the trunk and shoulders caused by overgrowth of yeast in the body. The skin colour may become lighter or darker than the surrounding skin
• Tinea barbae (barber's itch) – red patches formed on the neck, cheeks and chin. Can become crusty and pus-filled

Causes and transmission

Fungal agents responsible for ringworm

Ringworm infections are caused by dermatophytes, which are filamentous fungi that attack and eat the keratin tissue. These dermatophytes are divided into different classes; Trichophyton (affecting hair, feet and nails), Microsporum (affecting skin and nails) and Epidermophyton (affecting the skin). When their environment becomes damp and hot, the fungi can grow abnormally, causing an infection.³

Modes of transmission

• From a person who has ringworm – it is possible to get ringworm after being in direct contact with someone who has it. To make sure the infection does not spread, people with ringworm should not share towels, clothing, combs and other personal items
• Animal that has ringworm – people may get ringworm from touching an animal affected by it. Various animals can spread ringworms, such as dogs and cats, especially puppies and kittens. Cows, pigs, horses and goats can also spread ringworm through direct contact with people
• Soil transmission/environment - Ringworm, caused by fungi, can live in places, especially damp areas, such as public showers and locker rooms. To avoid this, it is a good idea not to walk barefoot in such places

Symptoms

Most signs will arise during 4-14 days after contact with fungi, causing these symptoms:¹ 

• Itching 
• Redness
• Circular, scaly rashes
• Hair loss (in scalp ringworm)
• Brittle or discoloured nails (in nail ringworm)
• Overlapping ring-like rashes

Diagnosis

Ringworm can be difficult to distinguish from other skin conditions due to its appearance, so there are several steps the doctor or the healthcare practitioner may take to confirm its diagnosis.^4,6

Physical examination and clinical history

During the physical examination, it is checked if you have a classic ringworm lesion that is a raised, red and scaly ring with a clear central area. The doctor will also check for other places where lesions may have formed. However, physical examinations are not enough to diagnose ringworm, so practitioners usually use diagnostic tests to confirm, before starting any treatment.

Microscopic examination of skin, hair, or nail samples

Testing the nail clippings with a periodic acid-Schiff (PAS) stain for confirmation of suspected onychomycosis, which is a nail infection caused by dermatophytes.

Wood's lamp examination 

Use of ultraviolet light for diagnosing ringworm caused by Microsporum class. This gives a fluorescent blue-green colour under a Wood’s lamp.⁵

Culture test

Fungal culture helps identify the fungus causing the condition, but results can take longer than usual.

Molecular testing (PCR)

Polymerase chain reaction is a quick and reliable method for diagnosis of ringworm.

Treatment 

There are several methods by which ringworm can be treated.^5,6

Topical antifungal medications

Antifungal creams and gels can work well, such as clotrimazole, terbinafine, tolnaftate and miconazole. If symptoms do not improve or clear up after two weeks, the doctor may prescribe oral medications.

Oral antifungal medications

Prescribed for more serious ringworm. Most medications are prescribed for about 1-3 months. These include:

• Itraconazole
• Griseofulvin
• Fluconazole
• Terbinafine

Home remedies 

Home remedies can have been shown to have little to no effect in treating ringworm. Apple cider vinegar can open up sores and tea tree oil has great antifungal and antimicrobial properties, however, its effects are still unknown.

Complications 

There are a few complications with ringworm¹:

• Spreading to other parts of the body
• Longer time to clear up for immune-compromised people
• Permanent damage, such as scarring (scalp ringworm)

Prevention 

It can be difficult to prevent ringworm since it is common and very contagious. But taking small precautions can help to prevent it:⁵

• Keeping clean – wash your hands often and keep shared areas, such as gyms, locker rooms, and schools, clean. Regular showers are advised
• Staying dry and cool – do not wear thick clothing for longer durations in warmer and humid weather
• Not sharing personal items – do not let others use your clothing, hairbrushes, towels and sports gear
• Avoiding infected animals – it is a good idea to ask your veterinarian in case of any doubt
• Educating others and yourself – be aware of the risk of ringworm and tell your children about ringworm and warn them about the infection

Public health considerations

A study from 2018, has shown that the management of ringworm has become an essential public health issue, because of the gap in the areas of pathophysiology and the management of the disease.⁷ Some of the treatment recommendations have shown to have lost their relevance in the current clinical scenario. It has also been shown that antimicrobial resistance to antifungal medication is increasing, meaning several medications are not effective or not killing the fungi and so it is continuing to grow, making it difficult to treat.

Summary

Ringworm is one of the most common types of fungal infections that affects various parts of the body, from the hair to the skin and nails. It is highly contagious, spreading even from the touch of an infected person or animal, but it is also treatable with various modes of treatment as advised to you by your doctor like the use of creams and for more serious symptoms, stronger antifungal medications. 

However, some recent studies have shown a rise in antimicrobial resistance and some fungi becoming resistant to the medications. There are also gaps in the management and the pathophysiology of the condition that should be studied further.