Tinea Capitis Clinical Presentation

• Tinea capitis begins as a small erythematous papule around a hair shaft on the scalp, eyebrows, or eyelashes.
• Within a few days, the red papule becomes paler and scaly, and the hairs appear discolored, lusterless, and brittle. They break off a few millimeters above the scalp skin surface.
• The lesion spreads, forming numerous papules in a typical ring form. Ring-shaped lesions may coalesce with other infected areas.
• Pruritus usually is minimal but may be intense at times.
• Alopecia is common in infected areas.
• Inflammation may be mild or severe. Deep boggy red areas characterized by a severe acute inflammatory infiltrate with pustule formation are termed kerions or kerion celsi (see the image below). Typical lesions of kerion celsi on the vertex scalp of a young Chinese boy. Note numerous bright yellow purulent areas on skin surface, surrounded by adjacent edematous, erythematous, alopecic areas. Culture from the lesion grew Trichophyton mentagrophytes. Courtesy of Skin Diseases in Chinese by Yau-Chin Lu, MD. Permission granted by Medicine Today Publishing Co, Taipei, Taiwan, 1981.
• Favus (also termed tinea favosa) is a severe form of tinea capitis.

  • Favus is a chronic infection caused most commonly by T schoenleinii and, occasionally, by T violaceum or Microsporum gypsum.
  • Scalp lesions are characterized by the presence of yellow cup-shaped crusts termed scutula, which surround the infected hair follicles.
  • Favus is seen predominantly in Africa, the Mediterranean, and the Middle East and, rarely, in North America and South America, usually in descendants of immigrants from endemic areas.
  • Favus usually is acquired early in life and has a tendency to cluster in families.
  • In favus, infected hairs appear yellow.

A variety of clinical presentations of tinea capitis are recognized as being inflammatory or noninflammatory and are usually associated with patchy alopecia. However, the infection may be widespread, and the clinical appearances can be subtle. In urban areas, tinea capitis should be considered in the differential diagnosis of children older than 3 months with a scaly scalp until proven negative by mycological examination. Infection may also be associated with painful regional lymphadenopathy, especially in the inflammatory variants.

Pertinent physical findings are limited to the skin of scalp, eyebrows, and eyelashes.

• Primary skin lesions of tinea capitis

  • Lesions begin as red papules with progression to grayish ring-formed patches containing perifollicular papules.
  • Pustules with inflamed crusts, exudate, matted infected hairs, and debris may be seen.
  • Black dot tinea capitis refers to an infection with fracture of the hair, leaving the infected dark stubs visible in the follicular orifices.
  • Kerion celsi may progress to a patchy or diffuse distribution and to severe hair loss with scarring alopecia (see the image below). Discrete patches of hair loss or alopecia caused by Trichophyton violaceum infection of the vertex scalp of a young Taiwanese boy. Courtesy of Skin Diseases in Chinese by Yau-Chin Lu, MD. Permission granted by Medicine Today Publishing Co, Taipei, Taiwan, 1981.
• Id reaction: Dermatophyte idiosyncratic or id reactions are manifestations of the immune response to dermatophytosis.

  • Id reactions occur at a distant site, and the lesions are devoid of organisms.
  • Id reactions may be triggered by antifungal treatment.
  • The most common type of id reaction is an acute vesicular dermatitis of the hands and feet. The grouped vesicles are tense, pruritic, and sometimes painful. Id reactions are noted in patients with inflammatory ringworm of the feet, primarily resulting from infection by Trichophyton mentagrophytes. Similar lesions may occur on the trunk in tinea capitis.
  • Vesicular lesions may evolve into a scaly eczematoid reaction or a follicular papulovesicular eruption.
  • Other less common types of id reactions include annular erythema and erythema nodosum. These patients have a strong delayed-type hypersensitivity reaction to intradermal trichophytin.
• Distribution of tinea capitis lesions: Skin lesions appear on the scalp with extension to the eyebrows and/or eyelashes.
• Regional lymph nodes: Cervical lymphadenopathy may develop in patients with severe inflammation associated with kerion formation.

• Infection of the scalp by dermatophytes usually is the result of person-to-person transmission. The organism remains viable on combs, brushes, couches, and sheets for long periods. Certain species of dermatophytes are endemic only in particular parts of the world. Zoophilic fungal infections of the scalp are rare.
• In the United States, T tonsurans has replaced M audouinii and M canis as the most common cause of tinea capitis. T tonsurans also is the most common cause of the disease in Canada, Mexico, and Central America.
• Historically, M audouinii was the classic causative agent in Europe and America and M ferrugineum was most common in Asia. Currently, M audouinii and M canis remain prevalent in most parts of Europe, although T violaceum also is common in Romania, Italy, Portugal, Spain, and the former USSR, as well as in Yugoslavia. In Africa, T violaceum, T schoenleinii, and M canis commonly are isolated.^[1]T violaceum and M canis are prevalent agents in Asia.^[2]T schoenleinii is common in Iran and Turkey, while M canis is common in Israel. Epidermophyton floccosum and T concentricum do not invade scalp hair. Trichophyton rubrum, which is the most common dermatophyte isolated worldwide, is not a common cause of tinea capitis.
• Dermatophytic fungi causing tinea capitis can be divided into anthropophilic and zoophilic organisms. Anthropophilic fungi grow preferentially on humans, and the most common type forms large conidia of approximately 3-4 µm in diameter within the hair shaft. Zoophilic fungi are acquired through direct contact with infected animals. Smaller conidia of approximately 1-3 µm in diameter typically are present, extending around the exterior of the hair shaft.
• Dermatophytosis customarily is divided into endothrix (inside the hair shaft) and ectothrix (extending outside the hair shaft) infection based on the location of proliferation of pathogenic fungi and destruction of the hair structure.
• Common causes of endothrix infection include T tonsurans, characterized by chains of large spores and T schoenleinii, characterized by hyphae with air spaces. Infected hairs break off sharply at the follicular orifice, leaving a conidia-filled stub or black dot. Suppuration and kerion formation (see the image below) commonly are associated with T tonsurans infection. Typical lesions of kerion celsi on the vertex scalp of a young Chinese boy. Note numerous bright yellow purulent areas on skin surface, surrounded by adjacent edematous, erythematous, alopecic areas. Culture from the lesion grew Trichophyton mentagrophytes. Courtesy of Skin Diseases in Chinese by Yau-Chin Lu, MD. Permission granted by Medicine Today Publishing Co, Taipei, Taiwan, 1981.
• In ectothrix infection, fragmentation of the mycelium into spores occurs just beneath the cuticle. In contrast to endothrix infection, destruction of the cuticle occurs. This type of infection is caused by T verrucosum, T mentagrophytes, and all Microsporum species.