Excerpt from Tinea Barbae

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Background

Tinea barbae is a superficial dermatophyte infection that is limited to the bearded areas of the face and neck and occurs almost exclusively in older adolescent and adult males. The clinical presentation of tinea barbae includes inflammatory, deep, kerionlike plaques and noninflammatory superficial patches resembling tinea corporis or bacterial folliculitis.

Pathophysiology

Tinea barbae is caused by the keratinophilic fungi (dermatophytes) that are responsible for most superficial fungal skin infections. They infect the stratum corneum of the epidermis, hair, and nails. Several enzymes, including keratinases, are released by dermatophytes, which help them invade the epidermis. The mechanism that causes tinea barbae is similar to that of tinea capitis. In both diseases, hair and hair follicles are invaded by fungi, producing an inflammatory response. Tinea barbae is caused by both zoophilic and anthropophilic dermatophytes.

Infection caused by zoophilic dermatophytes usually is of greater severity than that produced by anthropophilic organisms. Thus, zoophilic dermatophytes are the primary cause of inflammatory kerionlike plaques, which most likely result from a more intense host reaction. Recently, kerion formation has been described as resulting from Trichophyton rubrum infection. T rubrum, an anthropophilic dermatophyte, can invade hair shafts and deeper tissues (although rarely), resulting in an inflammatory reaction. Usually, infection involving hair is more severe; therefore, tinea barbae caused by anthropophilic dermatophytes often has a more severe course than tinea corporis caused by the same pathogen.

The formation of kerion is postulated by 2 theories. The first theory suggests that it results from diffusion of metabolites and/or toxins from the fungus; however, kerion formation most likely results from an immunologic response to dermatophyte antigens.

Frequency

United States

Tinea barbae is uncommon in the United States.

International

Currently, tinea barbae is infrequent around the world. As with other dermatophytoses, it is more common in countries in which weather is characterized by high temperatures and humidity. Tinea barbae was observed more frequently in the past before single-use razors became available, and infection frequently was transmitted by barbers who used unsanitary razors. Therefore, it is not surprising that tinea barbae once was termed barber's itch. Now that habits and equipment have changed, this source of infection has been all but eliminated. Currently, tinea barbae is more common among rural inhabitants, and zoophilic dermatophytes constitute its primary pathogens.

Mortality/Morbidity

Permanent alopecia and scarring frequently follow spontaneous resolution of inflammatory plaques and nodules. In superficial chronic tinea barbae, alopecia may occur in the center of the lesions; however, this is not common.

Sex

Men are affected almost exclusively because the disease involves the bearded areas of the face and neck. Involvement of the same areas in healthy women and children is classified as tinea faciei.

Age

Hair appears on the face at puberty; therefore, tinea barbae may occur almost exclusively in older adolescent and adult males.

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