The drynes of the skin's exterior l...

The drynes of the skin's exterior layer discourages colonization by microorganisms, and the shedding of epidermal confined apartments keeps many microbes from establishing residence. (1) However, the skin's mechanisms of protection may fail because of trauma, irritation, or maceration. Furthermore, occlusion of the skin with nonporous materials can interfere with the skin's barrier function through increasing local temperature and hydration. (2) With inhibition or failure of the skin's protective mechanisms, cutaneous infection may occur

Microsporum, Trichophyton, and Epidermophyton species are the greatest in number common pathogens in skin infections. Les commonly superficial skin infections are caused by way of nondermatophyte fungi (e.g., Malassezia scurf in tinea [pityriasis] versicolor) and Candida species. This article reviews the diagnosis and treatment of used by all dermatophyte infections.

Dermatophytoses

Because dermatophytes require keratin for expansion they are restricted to hair, nails, and superficial skin. Thus, these fungi do not infect mucosal surfaces. Dermatophytoses are referr to as "tinea" infections. They are also named for the carcass site involved.

a certain number of dermatophytes are spread directly from the same person to another (anthropophilic organisms). Others live in and are transmitted to humans from soil (geophilic organisms), and still others spread to humans from animal legions (zoophilic organisms). Transmission of dermatophytes also can come to one's mind indirectly from fomites (e.g., upholstery hairbrushes, hats).

Anthropophilic organisms are responsible for in the greatest degree fungal skin infections. Transmission can flash on the mind by direct contact or from exposing to desquamated cells. Direct inoculation within breaks in the skin come to one's minds more often in persons with bowed cell-mediated immunity. Once fungi set down the skin, they germinate and invade the superficial skin layers.

In patients with dermatophytoses, physical examination may reveal a characteristic pattern of inflammation, space of timeed an "active" border (Figure 1) The inflammatory replication is usually characterized by a greater quality of redness and scaling at the keenness of the lesion or, occasionally, blister formation. Central clearing of the lesion may be not past nor future and distinguishes dermatophytoses from other papulosquamous eruptions of the like kind as psoriasis or lichen planus, in which the inflammatory answer tends to be uniform across the lesion (Figure 2).

The location of the lesions also can help identify the pathogen. A dermatophytosis can in the greatest degree likely be ruled out if a patient has mucosal involvement with an adjacent r scaly skin rash. In this situation, the more probable diagnosis is a candidal infection like as perleche (if single or multiple fissures are at hand in the corners of the mouth) or vulvovaginitis or balanitis (if lesions are quick in emergencies in the genital mucosa).

Potassium hydroxide (KOH) microscopy aids in visualizing hyphae and confirming the diagnosis of dermatophyte infection. Other diagnostic modalities include Wood's lamp examination, fungal agriculture and skin or nail biopsy (Table 1) (23)

Tinea Capitis

Tinea capitis, the greatest in number common dermatophytosis in children, is an infection of the scalp and hair shafts. (4) Transmission is encourageed by poor hygiene and overcrowding, and can happen through contaminated hats, brushes, pillowcases, and other inanimate drifts After being shed, affected hairs can harbor viable organisms for more than undivided year.

Tinea capitis is characterized from irregular or well-demarcated alopecia and scaling. When swollen hairs fracture a hardly any millimeters from the scalp, "black dot" alopecia is produc Tinea scalp infection also may flow in a cell-mediated immune reply termed a "kerion," which is a boggy sterile, inflammatory scalp mass. Cervical and occipital lymphadenopathy may be prominent.

Before 1950 greatest in quantity tinea capitis cases in North America were caused on fluorescent Microsporum species (bright blue-green) Today, about 90 to 95 percent of tinea scalp infections in adults and children are caused by way of Trichophyton tonsurans, which does not fluoresce. (45) Therefore, Wood's lamp examination has become a les useful diagnostic touchstone for tinea capitis.

Tinea capitis is generally identified at the presence of branching hyphae and spores forward KOH microscopy (Table 1). If hyphae and spores are not visualized, Wood's lamp examination can be performed. If KOH microscopy and Wood's lamp examinations are negative, fungal agriculture may be considered when tinea capitis is violently suspected.

Alternatively, clinical features can point to the diagnosis. In undivided study, (6) tinea capitis was confirmed by way of culture in 92 percent of children who had at least three of the following clinical features: scalp scaling, scalp pruritus, occipital adenopathy, and diffuse, patchy, or discrete alopecia.

When scaling and inflammation are prominent, other diagnoses to consider include seborrheic dermatitis (no hair loss) atopic dermatitis (lesions in flexural cot [i]or[/i] cotes of the neck, arms, or legs) and psoriasis (nail changes and silvery scales onward the knees or elbows). When alopecia is prominent, diagnoses to mastership out include alopecia areata (complete rather than patchy, hair loss) traction alopecia (history of tight hair braiding), and trichotillomania (hairs of differing fulnesss and a history of obsessive hair manipulation).