Dermatophytosis
Dermatophytosis, commonly known as tinea, is a superficial fungal infection affecting the skin, hair, and nails, caused by dermatophytes—fungi that thrive on keratinized tissues. The condition is classified based on the infected area, with types including tinea pedis (athlete's foot), tinea capitis (scalp), tinea corporis (body), and tinea unguium (nails). Symptoms can vary but often include inflammation, itchiness, and changes in skin or nail appearance, such as cracking or discoloration.
Risk factors for developing dermatophytosis include direct contact with infected individuals or surfaces, preexisting skin injuries, and conditions that compromise the immune system. Diagnosis typically involves microscopic examination of skin or nail scrapings, and treatment may include topical or systemic antifungal medications. Preventive measures focus on minimizing contact with infected sources and maintaining good hygiene. Understanding dermatophytosis is essential for effective management and prevention of its spread, particularly in communal environments.
Dermatophytosis
- ANATOMY OR SYSTEM AFFECTED: Feet, hair, head, nails, scalp, skin
- ALSO KNOWN AS: Tinea
Definition
Dermatophytosis is a superficial fungal infection of the skin, hair, and nails caused by dermatophytes. The condition is generally classified according to the location of the infection. It is often referred to as tinea because it resembles infections caused by parasitic worms that burrow beneath the skin.
Causes
Dermatophytes are fungi that can grow and colonize on keratinized, or nonliving, tissues of human and animal hosts. The genera of fungi that most commonly cause dermatophytosis are Microsporum, Epidermophyton, and Trichophyton. These fungi usually remain on the outer layer of the skin in healthy people and generate metabolic by-products that trigger an allergic and inflammatory response.
Risk Factors
Dermatophytosis can occur in healthy persons who come in direct or indirect contact with dermatophytes. Exposure to common transmission routes, such as shower stalls containing the species that causes athlete’s foot, can increase the risk of infection. Preexisting injuries to the skin, such as scars, burns, and excessive temperature and humidity, also can increase susceptibility to infection. Immunocompromised persons, such as those with human immunodeficiency virus (HIV) infection or with acquired immunodeficiency syndrome (AIDS); persons with chronic disease; and persons who are sick or older are at increased risk of severe, subcutaneous, chronic, and recurrent dermatophytosis.
Symptoms
The symptoms of dermatophytosis vary according to the type of fungus involved and the location of the infection. The different types of dermatophytosis include tinea barbae (ringworm of the beard), tinea capitis (blackdot ringworm, or ringworm of the scalp and hair), tinea corporis (ringworm of the body), tinea cruris (jock itch, or ringworm of the groin), tinea pedis (ringworm of the foot, or athlete’s foot), tinea manuum (ringworm of the hands), and tinea unguium (ringworm of the nail). All cause inflammation that can be mild to severe, and many cause varying degrees of itchiness.
The common symptoms of athlete’s foot, for example, include cracked, flaking, and peeling skin between the toes; red and sometimes blistering, oozing, or crusting skin; and itching, burning, or stinging sensations. Athlete’s foot can also affect the toenails, causing them to become discolored, thick, and crumbly.
Screening and Diagnosis
The diagnosis of dermatophytosis is made by the presence of fungi in skin, nail, and scalp scrapings seen under microscopy or by the isolation of fungi in culture. Information obtained during the patient history and physical examination, such as the appearance of the lesion, travel history, animal contacts, and race, are also helpful in diagnosing dermatophytosis. A Wood's lamp examination, which uses ultraviolet light to look at skin, may also be useful.
Treatment and Therapy
The treatment of dermatophytosis varies according to the type of infection. Both topical and systemic antifungal agents are used. Antibiotics may also occasionally be necessary to treat secondary bacterial infections that occur due to scratching. In the case of tinea capitis, treatment often includes oral antifungal agents such as fluconazole, griseofulvin, terbinafine, and itraconazole, as well as a medicated shampoo to reduce the spread of infection.
Prevention and Outcomes
Dermatophytosis can be transmitted by direct contact with infected people and animals and by indirect contact with organisms on exfoliated skin or hair found in the environment. Reducing or eliminating exposure to infected hosts and contaminated objects, such as combs, shoes, and locker room floors, can help prevent dermatophytosis. Prompt treatment can also help prevent the spread of the organisms to other parts of the body and other people.
Bibliography
Berger, T. G. "Dermatologic Disorders." Current Medical Diagnosis and Treatment 2011, edited by Stephen J. McPhee and Maxine A. Papadakis. 50th ed., McGraw-Hill Medical, 2011.
Burns, Tony, et al., editors. Rook’s Textbook of Dermatology. 8th ed., 4 vols., Wiley-Blackwell, 2010.
Gupta, Aditya K., et al. "Dermatophytosis: The Management of Fungal Infections." Skinmed, vol. 4, no. 5, 2005, pp. 305-10, doi:10.1111/j.1540-9740.2005.03435.x. Accessed 30 Oct. 2024.
Hernández, Anna, et al. "Dermatophyte Infection." Osmosis, 11 Dec. 2020, www.osmosis.org/answers/dermatophyte-infection. Accessed 30 Oct. 2024.
Jartarkar, Swapna R., et al. "Pathogenesis, Immunology and Management of Dermatophytosis." Journal of Fungi, vol. 8, no. 1, 31 Dec. 2021, p. 39, doi:10.3390/jof8010039. Accessed 30 Oct. 2024.
Wolff, Klaus, and Richard Allen Johnson. Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology. 6th ed., McGraw-Hill Medical, 2009.
"Wood's Lamp Examination." Cleveland Clinic, 17 June 2022, my.clevelandclinic.org/health/diagnostics/23292-woods-lamp-examination. Accessed 30 Oct. 2024.