eMedicine Specialties > Emergency Medicine > Infectious Diseases

Tinea

Author: Rashid M Rashid, MD, PhD, Post-Graduate Year 2 and House Staff Resident, Department of Dermatology, MD Anderson Cancer Center, University of Texas and The Morzak Center
Coauthor(s): Andrew C Miller, MD, Chief Resident and Clinical Assistant Instructor, Departments of Emergency Medicine and Internal Medicine, State University of New York Downstate Medical Center, Kings County Hospital Center; Mark A Silverberg, MD, FACEP, MMB, Assistant Professor, Assistant Residency Director, Department of Emergency Medicine, State University of New York Downstate College of Medicine; Consulting Staff, Department of Emergency Medicine, Staten Island University Hospital, Kings County Hospital, University Hospital, State University of New York Downstate at Brooklyn
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Updated: May 12, 2009

Introduction

Background

The dermatophytes are a group of fungi (ringworm) that invade the dead keratin of skin, hair, and nails. Several species of dermatophytes infect humans; these can be divided into superficial and deep forms. This article focuses on superficial fungal infections that mainly belong to the Epidermophyton, Microsporum, and Trichophyton genera. These are more common and more likely to be seen in the ED. More detailed information can be found in the Dermatology section on deep fungal infections that can be life threatening in presentation, most often present in those with little or no immune response ability, and require immediate dermatologic consultation. 

Dermatophytosis is a superficial fungal infection caused by dermatophytes. The infection may spread from person to person (anthropophilic), animal to person (zoophilic), or soil to person (geophilic). The most common of these organisms are Trichophyton rubrum, Trichophyton tonsurans, Trichophyton interdigitale and/or Trichophyton mentagrophytes, Microsporum canis, and Epidermophyton floccosum.

The term phyton is derived from the Latin/Greek word for plant. Thus, dermato (skin) phyte (plant) was generated as a descriptive early term for tinea on the skin.

Pathophysiology

Dermatophytes are keratinophilic fungi and have the ability to invade keratinized tissue (eg, hair, nails, any area of the skin) but are restricted to the dead cornified layer of the epidermis. Humid or moist skin provides a very favorable environment for the establishment of fungal infection. Clinically, tinea infections are classified according to the body region involved/infected:

• Tinea capitis - Scalp
• Tinea corporis - Trunk and extremities
• Tinea manuum and tinea pedis - Palms, soles, and interdigital webs
• Tinea cruris - Groin
• Tinea barbae - Beard area and neck
• Tinea faciale - Face
• Tinea unguium (onychomycosis) - Nail

• Ectothrix species: Conidia form on the exterior of the hair shaft. The cuticle is destroyed and involved areas fluoresce a green-yellow under a Wood lamp. This is caused by Microsporum canis, Microsporum distortum, Microsporum ferrugineum, Microsporum audouinii, as well as nonfluorescent Trichophyton rubrum, Trichophyton verrucosum, Trichophyton megninii, Trichophyton mentagrophytes, Microsporum gypseum, and Microsporum nanum.
• Endothrix species: Conidia form within the hair shaft, and each is filled with hyphae and spores. The cuticle is not affected, and hairs do not fluoresce under a Wood lamp. This is caused by anthropophilic (Trichophyton rubrum, Trichophyton gourvilii, Trichophyton tonsurans, Trichophyton violaceum, Trichophyton yaoundei, Trichophyton soudanense).
• Favus species: Hyphae arrange within and around the hair shaft. This is a rare and severe form resulting in favus-like crusts or scutula and hair loss with honey comb destruction of the follicles. This is caused by Trichophyton schoenleinii.

Frequency

United States

Fungal infection occurs worldwide. Tinea pedis is the most common type in the United States and in the rest of the world.

Tinea capitis (ringworm of the head) is the most common dermatophytosis of childhood.
 
Tinea corporis is present in all ages, although it is more frequent in adolescents and pregnant females.

Onychomycosis is a common problem, especially in adults. In a survey in the United States, the prevalence of onychomycosis was approximately 3% in males and 1.4% in females. In a sample of North American children, 0.44% had onychomycosis.¹

International

International prevalence of tinea has ranged from 1-14%.^2,3

T rubrum is the most common cause of tinea corporis, tinea cruris, tinea pedis, and nail infection worldwide.

Mortality/Morbidity

• Cellulitis in the lower extremities, which causes a breach in the skin and allows the inoculation of opportunistic bacteria, is a frequent complication of interdigital fungal infection.
• In patients with impaired cell-mediated immune function, atypical and locally aggressive presentations of dermatophyte infection may occur. These include extensive skin disease, subcutaneous abscesses, and dissemination.

Race

Fungal infection affects all races; however, the prevalence of organisms varies by country.

Sex

Both sexes are affected by fungal infection. Tinea cruris is much more common in males because of the male anatomy, which allows moisture to accumulate in the crural folds.

Age

• Fungal infection affects all ages.
• Tinea capitis mainly is a disease in children; however, adults can be affected.
• Tinea cruris, tinea pedis, and onychomycosis predominantly affect the adult population.

Clinical

History

• It takes about 2 weeks from inoculation to subsequent skin changes that are clinically visible.
• Pruritus (itching) is the main symptom in most forms of tinea. Findings can be subtle and care must be taken in examination, as a novel form of delusional tinea has been described in several reports.⁴
• Patients with tinea capitis have hair loss. Infected hairs are brittle and break easily.
• Asking the patient about participation in sports, such as judo, karate, wrestling, and other contact sports, is important. Likewise, asking the patient about military enrollment and any contacts with similar skin disease is important.

Physical

At physical examination, the various types of tinea may have different findings, as follows:

• Tinea capitis
  • The clinical appearance of fungal infection of the scalp varies depending on the type of hair invasion.
  • Alopecia (hair loss), with hairs breaking at the scalp surface, usually is present.
• Tinea corporis
  • Infection typically is on the exposed skin of the trunk and extremities.
  • It is characterized by annular scaly plaques with raised edges, pustules, and vesicles. This is usually tinea imbricata (Trichophyton concentricum).
  • Tinea corporis gladiatorum is seen on the head, neck, and arms, in a distribution consistent with the areas of skin-to-skin contact in wrestling.
• Tinea pedis
  • This is a fungal infection of the toe webs and plantar surface and often affect only one foot.
  • Toe-web scaling, fissuring, and maceration; scaling of soles and lateral surfaces; erythema; vesicles; pustules; and bullae may be present.
• Tinea manuum
  • This is a fungal infection of the palms and finger webs that usually occurs in association with tinea pedis.
  • Usually, only one hand is involved.
  • Scaling and erythema may be present.
• Tinea cruris
  • It is a dermatophytic infection of the groin and pubic region.
  • It is characterized by erythematous lesions with central clearing and raised borders.
  • Tinea cruris often co-occurs with tinea pedis or tinea unguium.
• Tinea barbae
  • The beard and neck area are affected.
  • Erythema, scaling, and pustules are present.
• Tinea unguium
  • Tinea unguium is also called onychomycosis; this is an infection of the nail.
  • It is characterized by onycholysis (nail plate separation from nail bed) and thickened, discolored (white, yellow, brown, black), broken, and dystrophic nails.
• Majocchi granuloma
  • This is a deep folliculitislike infection.
  • Majocchi granuloma is kerionlike, characterized by erythema and nodules.⁵
• Id reaction (ie, identity reaction)
  • Id reaction is a fungus-free eruption that can resemble tinea.
  • Is secondary to a tinea infection at another site, is due to  cell-mediated immunity, and resolves with treatment of tinea.

Causes

The various tinea infections are caused chiefly by species of the genera Microsporum, Trichophyton, and Epidermophyton.

Tinea corporis is mainly caused by T tonsurans and also by M canis and T rubrum.

Risk factors for tinea infection include the following:

• Moist conditions
• Communal baths
• Immunocompromised states
• Cushing syndrome
• Atopy
• Genetic predisposition
• Athletic activity that causes skin tears, abrasions, or trauma such as wrestling, judo, or soccer

• Search for CME/CE on This Topic »

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