Tinea is a collective term for a group of fungal infections that affect the skin, hair, and nails. These infections are caused by dermatophytes, a type of fungus that thrives in warm, moist environments. Although most individuals develop resistance to skin fungi following an infection, some people exhibit a genetic susceptibility to tinea infections, which may run in families. The clinical presentation of tinea infections varies depending on the affected body part, and various antifungal treatments are available for management.
Types of Tinea Infections
Tinea Pedis (Athlete’s Foot)
Tinea pedis is a superficial fungal infection of the foot. It is the most common dermatophyte infection, affecting only humans. It is primarily transmitted through direct contact, often occurring in communal areas like bathrooms and gyms. The condition is exacerbated by wearing non-breathable footwear, such as leather or plastic shoes. It is relatively rare in children. The infection typically presents with peeling, itching, and erythema, often between the toes (especially between the fourth and fifth toes). It can also affect the soles of the feet, resulting in scaling, itching, and occasionally blistering. In severe cases, it may involve both feet. Tinea pedis is also a common precursor to onychomycosis (nail fungus).
Onychomycosis (Tinea Unguium)
Onychomycosis is a fungal infection of the toenails (and, less commonly, the fingernails). It is more common in men and commonly associated with concurrent tinea pedis. It often begins with an infection of the great toenail, especially following trauma. The nail typically becomes yellow, thickened, brittle, and prone to breaking. Treatment can be challenging, and it often requires prolonged antifungal therapy.
Tinea Cruris (Jock Itch)
Tinea cruris, commonly known as jock itch, typically affects the groin area and is more common in men than women. It is often associated with tinea pedis, particularly in individuals who sweat excessively. The infection manifests as an itchy, red rash with a well-defined border, often spreading from the groin area to the inner thighs.
Tinea Corporis (Ringworm)
Tinea corporis refers to a fungal infection of the body that is not limited to the areas covered in other tinea subtypes. It can spread from person to person through direct contact or by exposure to infected animals (most often cats) or contaminated soil. The infection typically presents as red, scaly, itchy patches, which may form a ring-like shape. Treatment usually involves topical antifungals, but if the infection originates from an animal, both the animal and the individual need treatment.
Tinea Capitis (Scalp Ringworm)
Tinea capitis is a fungal infection of the scalp, primarily affecting children. It often results in scaling, hair loss, and patchy bald areas. This condition is particularly prevalent in African American communities. Although treatment usually results in normal hair regrowth, complications such as kerion, an inflammatory form of tinea, may occur. A kerion resembles a boil or abscess and can result in permanent hair loss if not treated promptly, often requiring corticosteroids like prednisone.
Mechanisms of Infection
Tinea infections are caused by dermatophytes, fungi that invade keratinized tissues, such as skin, hair, and nails. These fungi thrive in warm, moist environments, and transmission typically occurs through direct contact with an infected individual or contaminated surfaces. Dermatophytes can also be transmitted by infected animals, particularly cats, and can survive in soil. Once the fungus comes into contact with the skin, it begins to grow and invade the outer layer of skin cells, leading to inflammation, itching, and the characteristic scaly patches.
Treatment Options
Treatment for tinea infections varies depending on the location and severity of the infection. Most cases are treated with topical antifungal medications, but oral medications may be required for more persistent or widespread infections.
- Topical Antifungals
Common over-the-counter treatments include Lamisil (terbinafine) and Micatin (miconazole). These medications are applied directly to the affected area and are generally effective for treating superficial infections such as tinea pedis, tinea corporis, and tinea cruris.
- Oral Antifungals
For more severe or persistent cases, such as tinea capitis, onychomycosis, or chronic tinea pedis, oral antifungal medications may be necessary. Commonly prescribed oral antifungals include:
Griseofulvin (Grispeg, Fulvicin) – a traditional first-line treatment for fungal infections of the skin and nails.
Terbinafine (Lamisil) – effective for treating tinea pedis, tinea corporis, and tinea unguium.
Itraconazole (Sporanox) – used for a variety of fungal infections, including tinea capitis and onychomycosis.
Fluconazole (Diflucan) – another oral antifungal commonly used for dermatophyte infections.
- Topical Treatment for Scalp Infections
For tinea capitis, selenium sulfide or ketoconazole shampoos may be used as adjunctive topical treatments, often in combination with oral antifungals.
- Inflammatory Tinea (Kerion)
In cases of kerion, where there is significant inflammation or abscess formation, systemic corticosteroids (e.g., prednisone) may be prescribed to reduce inflammation and prevent scarring or permanent hair loss.
Prevention
Prevention of tinea infections involves minimizing exposure to the fungi and maintaining good hygiene. Some key preventive measures include:
- Foot Hygiene
For tinea pedis, it is essential to keep feet dry by wearing breathable footwear and avoiding closed shoes that promote moisture buildup. After washing, thoroughly dry the feet, especially between the toes. Open-toed sandals or shoes can help keep feet dry.
- Avoiding Shared Spaces
Since tinea is spread via direct contact, avoiding walking barefoot in communal areas such as gym locker rooms, public showers, and pools can reduce the risk of infection.
- Treatment of Infected Individuals and Pets
Individuals with tinea infections should avoid close contact with others until the infection has been treated. Additionally, if the infection is believed to have been transmitted by an animal, the animal should also receive antifungal treatment.
- Maintaining Skin Hygiene
Regular washing of the skin, especially in areas prone to sweating, can help prevent fungal overgrowth.
Conclusion
Tinea infections are common dermatophyte infections that affect different parts of the body, including the feet, nails, scalp, and groin. While most superficial tinea infections can be effectively treated with antifungal creams, more severe cases, such as tinea capitis or onychomycosis, may require prolonged or systemic treatment. Preventive measures, such as maintaining foot hygiene, avoiding communal spaces, and treating infected individuals and animals, can help reduce the risk of fungal infections.
References
Mayo Clinic. (2021). Tinea (ringworm) infections. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/ringworm/symptoms-causes/syc-20351048
Diao, P., & Wang, Y. (2019). Efficacy of oral antifungal therapy for the treatment of onychomycosis: A meta-analysis of randomized controlled trials. Journal of Dermatological Treatment, 30(1), 1-10. https://doi.org/10.1080/09546634.2018.1484432
Rich, P., & Tan, M. (2020). Tinea capitis: Current concepts. Journal of Clinical and Aesthetic Dermatology, 13(10), 31-35. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7587752
