Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at February 23, 2016

Dermatophytosis, also known as ringworm or tinea is a skin infection that is common worldwide and caused by a group of fungi called dermatophytes. The number of cases is unknown due to the fact that many people will treat it themselves if they discover a rash.


Definition & Facts

Ringworm is not actually caused by a worm at all. It is a fungal infection that can affect the skin, hair, and nails. The term "ringworm" came about because the infection is often seen on the skin as a flat and round area that is irritated, scaling, and painful.

The infection can be seen in humans and animals and is passed through spores emitted from the fungus. Once afflicted by the spore, the infection can be seen on the skin between four and ten days. Dermatophytes metabolize and exist on the keratin in the skin, hair and nails. There are different subtypes which include:

Symptoms & Complaints

Symptoms of dermatophytosis can vary. There would be an area of infected skin that spreads outwards. A round, red and irritated patch would appear and the outside tends to be more red, raised and inflamed, therefore looking like a ring. The reason the skin turns red is because the fungal spores are infected and the infection spreads out into a circle. The rash may also develop blisters and begin to ooze.

If ringworm is found on the scalp, there will first be a small pimple that becomes larger. If not treated, ringworm on the scalp can lead to bald patches. If found on the foot, symptoms can include dry skin, itchy skin, and cracking skin. Ringworm can also be found on the nails and the symptoms include nail discoloration, thickening of the nail bed and brittleness.

If found in the groin area, the rash will be extremely itchy. The rash from jock itch may be mildly irritating or very painful, itchy, and inflamed. The severity of pain and irritability varies on which type of fungus is causing the infection.


The cause of dermatophytosis is fungus, and over forty species of fungus species can cause it. Three fungi that cause ringworm are Microsporum, Epidermophyton, and Trichophyton. One of the species of Microsporum, Microsporum canis is spread by cats and dogs.

The fungi are tiny spores that can survive on a person's skin for months at a time. Once fungi enter the skin, they germinate and invade the skin layers. Fungus thrives off of warm moist environments including swimming pools, locker rooms, and folds of the skin. Another cause of this infection is the combination of hot weather and tight clothing which allows for the production of fungus.

Ringworm is contagious and can be spread by contact of the skin, sharing towels, clothing and sports equipment. A lot of people will develop this infection by walking around barefoot in a locker room or using public showers. People who have ringworm on their feet can accidentally spread the infection to their hands and groin area.

Diagnosis & Tests

It is wise to visit a physician's office if there is any sort of abnormality on the skin. Health care providers typically diagnose ringworm by first checking the area of the skin that is infected via physical examination. They would then take some scrapings of the rash on the skin, scalp, or nail and analyze it under a microscope to check for fungus. The scrapings would be done using a blunt scalpel, a bone curette, or tweezers.

Skin and nail scrapings are usually scraped onto black cards so that it is easier for the doctors to see how much of the specimen they have collected. In order for there tto be a correct laboratory diagnosis, physicians need to make sure that they submit an adequate amount of clinical material to be analyzed so that the laboratory can perform both microscopic examination and a fungal culture.

A KOH test may be conducted in which the sample is placed on a slide with potassium hydroxide solution and is heated. The doctor will then look at the slide under a microscope and tell if there are fungus cells present. A culture is often more reliable than a microscopic exam because it is will accurately identify the kind of fungus that is involved. Once sent to the lab, results should be available within twenty-four hours of the submission.

Treatment & Therapy

Treatment for ringworm usually depends on where the infection is located. For instance, rashes that are on the scalp or nails need different treatment than rashes on the skin. Ringworm of the skin such as jock itch or athlete's foot is treated with antifungal topical medication. The ointments would be placed directly on the rash to kill fungi. Terbinafine, miconazole nitrate, and tolnaftate are several commonly found antifungal ingredients in over-the-counter topical medications.

However, if the rash covers a vast area of the skin or does not go away using the topical creams, an antifungal oral pill may be needed for treatment. Oral treatments include fluconazole and itraconazole. The rash can clear up as soon as a person starts the treatment as long as they use it consistently. Treatment can take two to four weeks.

Prevention & Prophylaxis

It is easy to prevent dermatophytosis from happening. It is important to keep the skin clean and dry and to wear loose-fitting clothing especially during the hot summer months. People should try to wear protective footwear when showering in public locker rooms and to make sure to dry the skin completely. Also, it is important to remember not to share clothing, towels, sports equipment, or sheets. Ringworm should not be feared, as it is a common rash that happens to many. If treatment is implemented right away the rash should clear up and life will go on free of itch and pain.