What Is Ringworm?

The typical ringworm lesions are usually round, scaly and reddened, in addition to causing intense itching. Learn more about this condition below.
What Is Ringworm?
Diego Pereira

Written and verified by el médico Diego Pereira.

Last update: 17 March, 2023

Did you know that ringworm is one of the most common skin infections? It’s caused by fungi related to keratin, and belongs to the group of superficial mycoses, as it affects the “upper” layers of the epidermis.

Due to the variety of clinical manifestations and causative agents, ringworm is usually subclassified according to the affected area. In general, the diagnostic process and treatment are fairly straightforward, although the latter tends to take several weeks.

We have prepared the following article with the most important information about the disease. If you’re interested in knowing a little more about it, keep reading!


Ringworm has many clinical manifestations
Ringworm can affect any part of the skin. When it occurs on the scalp, it’s often associated with hair loss.

The clinical manifestations can vary depending on the area of the body that’s affected. In fact, this allows the different types of ringworm to be classified. We’ll describe the most important ones below:

  • Ringworm of the body: Although in most cases it affects the trunk of the body, in reality this term applies to the face and part of the extremities. Small, circular, and red lesions are usually present (especially at their edges), which, over time, grow and begin to flake.
  • Ringworm of the head: Also known as tinea capitis, it’s usually caused by Microsporum canis, although this depends on the geographical location. It usually causes circular, scaly lesions, associated with itching and hair loss. In rare conditions, a serious inflammatory complication called kerion of Celsus can occur.
  • Ringworm of the groin: This is characterized by affecting the inner thighs at their junction with the inguinal region. Like the other types of ringworm, the lesions can worsen under specific conditions such as damp and darkness, something that characterizes this area.
  • Ringworm of the nails: This is a fairly characteristic type in which the nails thicken, acquire a yellowish color, and can begin to detach from the nail bed. It usually motivates the consultation due to the aesthetic consequences that it tends to cause.


As it’s an infection, the cause of the different types of ringworm is a consequence of the proliferation of the causative microorganism. In this case, they’re known as dermatophytes, a type of fungi that have an affinity for keratin, an abundant substance on the surface of the skin. In fact, it’s a fundamental part of the horny layer of the epidermis.

There are several genera and species within this group, and its prevalence depends on the area and the type of ringworm being considered. According to research work carried out in Spain, the microorganisms most involved in that country are usually Trichophyton rubrum, T. mentagrophytes and Microsporum canis.

Experts at the Mayo Clinic help us understand how this disease can be acquired. This requires close and prolonged contact with other humans, animals, objects, or the ground. Infection and symptoms will occur when the germ involved manages to overcome the natural barriers of the skin’s immune system.


Different research explains that the diagnosis of ringworm depends to a great extent on the medical history. The presence of risk factors, the clinical course, and the appearance of the lesions are often helpful in establishing the diagnosis.

However, there are clear methods to confirm the condition. The direct examination of dermatophytes under the microscope and with the help of potassium hydroxide (KOH) at 10% is a fairly effective, fast, and inexpensive technique. Samples are usually obtained by “scraping” the active edges of the lesion concerned.

On the other hand, it’s possible to carry out specific cultures to observe the growth of fungi and allow the identification of species and genus. As it takes longer to produce results, it’s more expensive and it isn’t always necessary to start the treatment – the culture isn’t usually carried out in the first instance.


Ringworm has different treatment modalities
There are many antifungals (available in creams or tablets) that are effective for different types of ringworm.

According to a publication in Medline Plus, the treatment of ringworm is usually limited to basic care and the application of creams with antifungal agents. The latter usually contains ketoconazole, miconazole, or terbinafine, which are very effective in eliminating dermatophytes.

In the case of extensive lesions, the doctor may prescribe one of these drugs orally, generally preserving the topical treatment. In addition, keeping the affected area dry and clean is essential in order to prevent the growth of fungi. Treatment can take several weeks.


Given the possibility of transmission through various objects (called fomites), it’s important to take the following recommendations into account:

  • Wash clothes, cloths or towels in regular use with hot water
  • Don’t reuse clothes when they’re dirty
  • Avoid moisture in affected areas
  • Wash with soap and water after playing sports or sweating profusely.


The characteristic ringworm lesions are often annoying and unsightly. For this reason, they can cause frustration and discomfort in those affected. Given the good response to treatment, it’s advisable to go to a dermatologist as soon as possible in order to receive the necessary instructions.

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