Dermatophytes are fungi that get nutrients from keratin for growth. They usually affect the skin, nails, and hair. The species that commonly invade the keratin are those that belong to the genus Trichophyton, Epidermophyton, and Microsporum. Fungal infections produce ring-like patterns on the different parts of the body and are commonly called as ringworm. Such skin conditions are usually treated using antifungals.
Fungal infections are classified based on their anatomic location:
- Body: Tinea corporis
- Scalp: Tinea capitis (ringworm of the scalp and hair shafts)
- Foot: Tinea pedis (athlete's foot)
- Groin: Tinea cruris (jock itch)
- Nails: Tinea unguium (onychomycosis)
Ringworm of the Scalp (tinea capitis)
This highly contagious fungal infection commonly affects school-age children and toddlers, but may also affect people of any age. Ringworm of the scalp or tinea capitis is characterized by scaly, bald, and itchy patches on the head. In some cases, individuals may develop severe inflammation that leads to permanent hair loss or scarring. The infection can spread from one person to another by using pillows, hats, or towels owned by an affected individual.
Scalp ringworm is caused by dermatophytes, which thrive in warm and moist areas of the body. Fungal infections tend to easily spread in overcrowded and dirty living areas. Pet animals, such as cats and dogs, can also be carriers of ringworm. Other carrier animals include horses, pigs, cows, and goats. Children can easily contract superficial fungal infections by playing or grooming their pets with ringworm.
Having itchy patches on the scalp is the most common symptom of scalp ringworm. Hair may also break off along with having scaly, bald, and red areas on the head. Some people with scalp ringworm may also have the following symptoms:
The formation of kerion (crusty and inflamed lesions) on the scalp develops in severe cases leading to scarring and permanent bald spots.
The doctor diagnoses scalp ringworm by initially performing a visual examination of the scalp. A diagnostic test called Wood's lamp examination may be used by the doctor to closely examine your hair or skin and identify any signs of infection. A sample of your skin or hair may also be collected and sent to the laboratory for further analysis. However, it may take a longer time for its processing, which is usually up to three weeks.
Treatment for scalp ringworm includes the prescription of oral antifungals and medicated shampoos.
Medicated shampoos usually contain the ingredients selenium sulfide and ketoconazole, which help prevent the spread of ringworm infection. These shampoos are often combined with oral antifungals to completely get rid of the infection. Medicated shampoos are usually used twice a week for one month.
The most commonly prescribed antifungals for ringworm are terbinafine hydrochloride (Lamisil) and griseofulvin (Gris-PEG, Grifulvin V). These oral antifungals are usually taken up to six weeks. However, they also have side effects, such as an upset stomach and diarrhea.
The side effects of griseofulvin may also include:
- Allergic reactions, especially those who have a penicillin allergy
- Skin rash or hives
- Feeling lightheaded or weak
- Photosensitivity (sun sensitivity)
Other side effects of terbinafine hydrochloride may include:
- Allergic reaction
- Skin rash or hives
- Skin itching
- Abdominal pain
- Impaired sense of taste
- Liver problems (only in rare cases)
Ringworm of the Body (tinea corporis)
Fungal infections that develop on top of the skin layer usually itch and are characterized by red circular patterns with a clear or smooth center. The term ringworm is used due to the physical characteristic of the fungal infection and not from actual worms.
Ringworm of the body is also closely related to the following fungal infections:
- Scalp ringworm (tinea capitis)
- Athlete's foot (tinea pedis)
- Jock itch (tinea cruris)
Ringworm usually spreads by direct contact with the infected skin of an animal or person. Mild ringworm can be easily treated using over-the-counter topical antifungals. However, individuals with severe ringworm may need to take oral antifungal medications.
Ringworm is caused by dermatophytes that attack the outer layer of the skin, hair, nails, and scalp because of the keratin contained in them. Ringworm can be spread through direct contact with infected animals or pets, such as cats and dogs. Other ways in which ringworm can be transmitted include:
- Direct skin-to-skin contact with a person infected with ringworm.
- Touching objects that are recently used by an infected person or animal. These objects include towels, combs, brushes, beddings, and clothing.
- Being exposed to an infected soil for a long time can also spread ringworm to humans.
Ringworm starts as scaly patches that appear flat on the skin. These patches may also be itchy and red with a slightly raised border that forms a roughly circular pattern. The interior of the ring-like pattern may be smooth, scaly, or may have red bumps. Some people may develop several rings that tend to overlap or merge together.
People who have an increased risk of being infected by ringworm include those who:
- Have an impaired immune system
- Taking medications that can weaken the immune system
- Have close and direct contact with other people or animals infected with ringworm
- Sharing of ringworm-contaminated objects (towels, clothing, or beddings)
- Frequently wear tight clothing
- Live in regions with a warm climate
- Engage in sports that involve skin-to-skin contact (football, wrestling)
Your healthcare provider usually asks about your medical history and performs a physical examination of the patches. To help determine the cause of your skin infection, the doctor may also collect a skin scraping sample from the infected area for further testing and analysis in the laboratory.
Ringworm of the body can be easily treated using over-the-counter antifungal (topical) medications. Topical antifungals are usually in the form of creams, ointments, or powder. They are directly applied to the affected skin areas.
Some of the most common over-the-counter topical antifungals are:
In severe ringworm cases, a stronger topical antifungal along with an oral antifungal medication may be prescribed. The most commonly prescribed oral antifungal is griseofulvin.