Inflammatory and non-inflammatory TB have to be distinguished clinically.

The former is caused by zoophilic dermatophytes and is associated with hardened efflorescences such as plaques and nodules. These efflorescences may be scattered throughout the affected area or concentrate in certain spots. In most cases, symptoms are first noted in the bearded areas of chin and neck and subsequently spread to the cheeks. Only severe TB comprises the entire bearded area of face and neck from the start. The lips are rarely affected.

Efflorescences are further characterized by their reddish color and the presence of pustules and sinuses on their surface. All over the affected area, hair becomes loose and can easily be removed. Upon closer inspection of such hair, it can be observed that hair roots are involved in a pus-like mass. The hair shaft is often broken.

In advanced stages of the disease, exudate starts to cover plaques and nodules and forms crusts. Also, systemic symptoms such as disturbed general condition, fever and lymphadenopathy may be developed.

Non-inflammatory TB is caused by anthropophilic dermatophytes. It occurs less frequently than inflammatory TB. Here, papules and crusts delimit erythematous spots. As is the case in inflammatory TB, infected hair tends to break. Patients suffering from chronic forms of non-inflammatory TB may present with small pustules affecting the hair follicles.

Of note, TB may run an asymptomatic course, but pruritus is usually present. In rare cases, tinea blepharociliaris may be observed in TB patients [8].

In order to diagnose TB, a fungal infection has to be detected [9]. Clinical examination may reveal indicative findings, but is usually not sufficient to confirm the diagnosis. Wood lamp examination is recommended since Microsporum canis is one of the most common causative agents of TB.

Microscopic analysis and fungal cultures are frequently necessary to confirm TB. Samples may consist in infected and recently depilated hair as well as material collected from pustules. In patients presenting with symptoms suspicious of chronic TB, scrapings from lesion borders should be examined. It is more likely to isolate fungi from lesion borders than from lesion centers. Microscopic analysis may provide rapid results and is easily available. However, it requires lots of experience to be able to identify hyphae and arthroconidia and to diagnose dermatophytoses. In order to prepare a microscopic examination, samples should be placed on a slide and be treated with 10-20% potassium hydroxide that may or may not contain dimethyl sulfoxide. It is recommendable to delay the examination for some minutes after adding potassium hydroxid. Analysis of warmed samples is somewhat easier. Special dyes such as chlorazol black E or Parker ink may help to recognize fungal pathogens.

Sabouraud agar supplemented with cycloheximide and chloramphenicol to avoid bacterial overgrowth is used to establish fungal cultures. Samples may need to be cultivated up to three weeks, which is the main disadvantage of this technique. However, detailed examination of potentially growing fungal colonies allows for the determination of the causative agent. Some microbiological laboratories may dispose of special media that may provide earlier results.

If TB cannot be confirmed nor ruled out after taking the aforementioned measures, a biopsy may be indicated. Folliculits and perifolliculits are the most common findings. Microabscesses may be observed. Affected areas are infiltrated by a variety of inflammatory cells. Lymphocytes may be present in the spongiotic follicular epithelium. Giant cells may be observed in biopsy samples obtained from chronic TB patients. In order to visualize fungal elements, Periodic Acid Schiff stain is recommended. Hyphae and arthroconidia may be encountered in hair follicles and within the hair shaft.

Similar to other dermatophytoses, treatment relies on oral antimycotics [10]. The treatment of choice consists in a daily dosis of 250 mg terbenafine and should be administered over the course of four weeks. This therapy has been recommended for different species of dermatophytes that may cause TB [11]. A therapy based on a daily dosis of 20 mg per kg gresiofulvin may serve as an alternative but should be continued at least eight weeks. Other therapeutic options include the administration of itraconazole at a dosis of 100 mg per day for approximately six weeks. In general, treatment periods should rather be based on the clinical evolution of the patient than on universal recommendations.

Topical use of antimycotic formulations is not sufficient to control TB but usually supplements systemic therapy. Azoles and allylamines may be used [12].

As for supportive measures, the affected areas should be shaved or depilated. Crusts should be softened with damp compresses in order to facilitate skin cleaning.

If at all possible, the source of the infection should be determined and eliminated. Tinea pedis, onychomycoses and other fungal infections should be treated. Also, antimycotic treatments are available for pets and livestock.

Prognosis is good. TB usually responds well to treatment. Even if left untreated, spontaneous remission of inflammatory TB is likely to occur within a few months. Tissue damage mediated by dermatophytes and aggravated by the patient's immune response may, however, leave scars and areas of alopecia.

Spontaneous remission may not occur in patients showing non-inflammatory TB. Here, the disease may become chronic. For further description of inflammatory and non-inflammatory TB, please see chapter presentation.

The old term "barber's itch" refers to the fact that TB was mainly transmitted by barbers who attended several men with the same instruments, an observation typical for infectious diseases.

Indeed, TB is caused by dermatophytes, very common fungal pathogens that also trigger tinea pedis (athlete's foot) and tinea cruris (jock itch). There are several species of dermatophytes that may cause TB and the majority of them corresponds to zoophilic dermatophytes that originate from pets or livestock [3], e.g. Trichophyton mentagrophytes var granulosum, Trichophyton mentagrophytes var erinacei, Trichophyton verrucosum and Microsporum canis. The most common triggers for TB are Trichophyton mentagrophytes var granulosum and Trichophyton verrucosum [4]. Trichophyton mentagrophytes var erinacei is transmitted by hedgehogs and thus less frequently detected [5]. Among anthropophilic dermatophytes, Trichophyton rubrum and Trichophyton violaceum are the most common causative agents. However, Trichophyton megninii and Trichophyton schoenleinii may also be detected in samples obtain from TB patients [6]. Elsewhere, Trichophyton interdigitale and Microsporum nanum and even Arthroderma benhamiae have been registered as causative agents of TB [7].

It has been reported that TB may be triggered by pathogens transmitted from the feet or other parts of the body by the patient themselves.

Dermatophytes release keratinolytic enzymes and thereby cause damage to the superficial layers of the skin. This results in rash and pruritus that, in turn, are aggravated by the patient's immune response. Efflorescences are frequently triggered by secondary bacterial infection.

The vast majority of TB cases corresponds to older adolescent and adult males because the disease affects the bearded areas of face and neck. If similar infections and symptoms occur in children or females of any age, the resulting disease is termed tinea faciei.

Although dermatophytes are distributed throughout the world, the current incidence of TB is rather low.This may be attributed to the disappearance of barbers and to the common use of single-use razors. Nowadays, rural populations show higher prevalence of TB and this may be due to the fact that they are more commonly exposed to zoophilic dermatophytes that colonize the skin of their animals. Furthermore, warm, humid climates seems to promote infections with dermatophytes and thus increase the incidence of diseases like TB.

Dermatophytes causing TB are keratinophilic fungi that may infect such tissues that contain keratin, e.g. the stratum corneum of the skin but also nails and hair. Deeper tissue layers are usually not affected. Dermatophytes release keratinolytic enzymes that facilitate tissue colonization that, in turn, most easily occurs through hair and hair follicles. This explains why the bearded area of face and neck is more susceptible to dermatophytoses. Mycotic infection provokes an immune response whose magnitude highly depends on the causative agent. In this context, zoophilic dermatophytes do usually account for more severe immune responses than anthropophilic dermatophytes. Kerions are often attributed to the intense immune response triggered by the former, but may also be caused by anthropophilic dermatophytes such as Trichophyton rubrum [6]. An alternative hypothesis regarding the formation of kerions states that certain species of dermatophytes may release toxins or metabolites that diffuse into the affected tissue. This hypothesis, however, is less accepted.

TB can largely be prevented by adopting certain hygiene routines.

In this context, razors and similar instruments should not be shared with other people and should be replaced regularly. This also applies for towels and further objects that may come into contact with other people's faces. Antimicrobial treatments should be applied to the face after shaving. Skin care is another important factor in TB prevention, since fungi may enter the skin via tiny lesions.

Additionally, the possibility to transmit pre-existing fungal infections from the feet or other parts of the body to the face should be considered. Adequate treatment of the former is the best option to eliminate this source of TB.

Because most causative agents originate from animals, hands should be washed after touching them. Dermatologic problems should be seen by a veterinarian and be treated accordingly.

Tinea barbae (TB) refers to a facial dermatophytosis affecting the bearded areas of face and neck [1]. The disease is almost exclusively detected in older adolescents and adult men. Its overall incidence has been decreasing for a long time because general hygiene measures have been adopted in large parts of the world.

TB is caused by distinct species of dermatophytes, the majority of which originate from pets and livestock [2]. However, anthropophilic dermatophytes may also be isolated from TB lesions. The inflammatory form of the disease is associated with hardened plaques and nodules that carry pustules, draining sinuses and crusts. In contrast, erythematous patches delimited by pustules and crusts characterize the non-inflammatory form of the disease.

TB patients respond well to treatments. Spontaneous remission is likely in cases of inflammatory TB, but may leave scars and areas of alopecia. Systemic antimycotic treatment is usually combined with topic administration of antimycotic drugs.

The term tinea barbae (TB) describes a skin disease affecting the bearded areas of face and neck in older adolescents and adult men. Therefore, it has often been referred to as "barber's itch".

Causes

The disease is caused by dermatophytes, i.e. fungal pathogens that may originate from animals, from other people or even from another part of the patient's own body. Most frequently, dermatophytes are contracted when touching an infected animal. Insufficient measures regarding face hygiene may also promote TB. In this context, razors or towels shared with other people suffering from TB may be the source of the causative fungi. Warm, humid climates facilitate pathogen development.

Trichophyton and Microsporum are the most common fungi triggering TB. These fungi release keratinolytic enzymes and thereby damage the outer layers of the skin and cause an immune response.

Symptoms

Physicians distinguish between inflammatory and non-inflammatory forms of TB. Both forms cause hair loss in the affected areas.

Inflammatory TB is usually caused by dermatophytes contracted from animals. It is typically characterized by itching, hardened plaques and nodules that generally develop in the bearded areas of chin and neck but may then spread to the cheeks. Crusts may form on the surface of these plaques and nodules.

Non-inflammatory TB may be associated with reddish patches that are delimited by pustules and crusts.

In some cases, no symptoms or only mild pruritus may be noted by TB patients.

Diagnosis

Clinical examination is usually not sufficient to diagnose TB. However, the appearance of skin lesions may indicate possible TB. This also applies to the results of an examination with a special lamp emitting UV-light. Certain parts of fungi become visible when illuminated with this lamp.

Hair and tissue samples may be taken and analyzed microscopically to detect the presence of dermatophytes. If such an examination does not yield concluding results, similar samples may be used to prepare a fungal culture.

Treatment

Hair remaining in the affected areas should be shaved or depilated. Crusts should be softened with damp compresses and need to be removed.

Drug therapy is based on systemic treatment and topic supplementation. In order to cure the disease, medication needs to be taken for up to eight weeks. Terbinafine, griseofulvin and itraconazole are compounds that mediate antimycotic effects. Prognosis is good.

If possible, the source of the disease should be identified and eliminated. Adequate hygiene measures should be implemented. If there are animals suffering from dermatophytoses, they should be treated.

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