Mycology – an update Part 2: Dermatomycoses: Clinical picture and diagnostics

Abstract

Summary Most fungal infections of the skin are caused by dermatophytes, both in Germany and globally. Tinea pedis is the most frequent fungal infection in Western industrial countries. Tinea pedis frequently leads to tinea unguium, while in the elderly, both may then spread causing tinea corporis. A variety of body sites may be affected, including tinea glutealis, tinea faciei and tinea capitis. The latter rarely occurs in adults, but is the most frequent fungal infection in childhood. Following antifungal treatment of tinea unguium and also tinea capitis a dermatophytid or hyperergic reaction to dermatophyte antigens may occur. Yeast infections affect the mucous membranes both of the gastro‐intestinal system and the genital tract as candidiasis mostly due to Candida albicans. Cutaneous candidiasis affects predominantely the intertriginous regions such as groins and the inframammary area, but also the intertriginous space of fingers and toes. In contrast, pityriasis versicolor is a superficial epidermal fungal infection primarily on the the trunk. Mold infections are rare in dermatology; they play a role nearly exclusively in nondermatophyte‐mold (NDM) onychomycosis. The diagnosis of dermatomycoses comprises the microscopic detection of fungi using the potassium hydroxide preparation or alternatively the fluorescence optical Blankophor preparation together with culture. The histological fungal detection with PAS staining possesses a high sensitivity, and it should play a more important role in particular for diagnosis of onychomycosis. Molecular biological methods, based on the amplification of fungal DNA with use of specific primers for the distinct causative agents are on the rise. With PCR, such as dermatophyte‐PCR‐ELISA, fungi can be detected directly in clinical material in a highly specific and sensitive manner without prior culture. Today, molecular methods, such as Matrix Assisted Laser Desorption/Ionization Time‐Of‐Flight Mass Spectrometry (MALDI TOF MS) as culture confirmation assay, complete the conventional mycological diagnostics.

Sensitization of Candida albicans to terbinafine by berberine and berberrubine

“…C. albicans, an opportunistic fungal pathogen that normally inhabits the mucous membranes of the gastrointestinal and female genital tracts (3), is able to attack the immunocompromised patients (4). When the normal microbial barrier is disrupted, C. albicans can invade the intestinal and female genital mucosal barriers and causes candidiasis and candidemia (5,6). A cross-sectional study has reported that Candida species isolation from the vaginal mucosa was more frequent in human immunodeficiency virus (HIV)-infected patients (29.7%) when compared with uninfected women (14.5%).…”

Tinea corporis caused byArthroderma benhamiaein a child

“…4 Guinea pigs are the most common source of A. benhamiae, but the organism has also been isolated from rabbits, cats and dogs. 3,5,6 In infected guinea pigs, the infection may manifest as circumscribed areas of alopecia with erythema, scaling and crusting, and onychomycosis, with brittle, irregular claws that lack lustre and are unusually coloured. 6 Diagnosis of A. benhamiae infection can be made by conventional identification of the dermatophyte by microscopic examination of isolates obtained from clinical material.…”

“…Amplification and sequencing of the ribosomal DNA ITS region and matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry can be used to confirm A. benhamiae in cultures growing Trichophyton species. 5 Widespread dermatophytosis due to Trichophyton species of A. benhamiae, in particular tinea capitis, requires oral antimycotics. Terbinafine has proven to be effective, with fluconazole and itraconazole as alternatives.…”

A study of 200 cases of pityriasis versicolor: the distribution of age, gender, blood group, lesion morphology, hemoglobin levels, cholesterol levels and diabetic status

“…1 It is particularly prevalent in tropical and subtropical regions like India. It is an opportunistic pathogen which infects skin when its commensal round yeast form transforms to the pathologic mycelial form.…”