SUMMARY: In the last 15 years, the genusMalasseziahas been a topic of intense basic research on taxonomy, physiology, biochemistry, ecology, immunology, and metabolomics. Currently, the genus encompasses 14 species. The 1996 revision of the genus resulted in seven accepted taxa:M. furfur,M. pachydermatis,M. sympodialis,M. globosa,M. obtusa,M. restricta, andM. slooffiae.In the last decade, seven new taxa isolated from healthy and lesional human and animal skin have been accepted:M. dermatis,M. japonica,M. yamatoensis,M. nana,M. caprae,M. equina, andM. cuniculi.However, forthcoming multidisciplinary research is expected to show the etiopathological relationships between these new species and skin diseases. Hitherto, basic and clinical research has established etiological links betweenMalasseziayeasts, pityriasis versicolor, and sepsis of neonates and immunocompromised individuals. Their role in aggravating seborrheic dermatitis, dandruff, folliculitis, and onychomycosis, though often supported by histopathological evidence and favorable antifungal therapeutic outcomes, remains under investigation. A close association between skin andMalasseziaIgE binding allergens in atopic eczema has been shown, while laboratory data support a role in psoriasis exacerbations. Finally, metabolomic research resulted in the proposal of a hypothesis on the contribution ofMalassezia-synthesized aryl hydrocarbon receptor (AhR) ligands to basal cell carcinoma through UV radiation-induced carcinogenesis.

Raman spectroscopy has emerged as a promising tool for real-time clinical diagnosis of malignant skin tumors offering a number of potential advantages: it is non-intrusive, it requires no sample preparation, and it features high chemical specificity with minimal water interference. However, in vivo tissue evaluation and accurate histopathological classification remain a challenging task for the successful transition from laboratory prototypes to clinical devices. In the literature, there are numerous reports on the applications of Raman spectroscopy to biomedical research and cancer diagnostics. Nevertheless, cases where real-time, portable instrumentations have been employed for the in vivo evaluation of skin lesions are scarce, despite their advantages in use as medical devices in the clinical setting. This paper reviews the advances in real-time Raman spectroscopy for the in vivo characterization of common skin lesions. The translational momentum of Raman spectroscopy towards the clinical practice is revealed by (i) assembling the technical specifications of portable systems and (ii) analyzing the spectral characteristics of in vivo measurements.

The recent sequencing of the whole genome of Malassezia globosa and M. restricta forms the basis for molecular epidemiology studies and instigates investigations into their respective virulence factors. Thus, reviewing current knowledge on Malassezia molecular typing methods would reveal the pros and cons of each method and would highlight potential scarcity of epidemiological data regarding this ubiquitous fungal commensal and pathogen. Methods employed for Malassezia molecular typing can be categorized into those detecting sequence variations of strains and those that selectively amplify polymorphic DNA markers for discriminating Malassezia species subtypes. The former exploit rRNA gene sequence variations in order to trace M. globosa, M. restricta and M. pachydermatis subtypes associated with specific skin diseases, or detect M. furfur geographical variations. Polymorphic DNA amplification methods, such as amplified fragment length polymorphism analysis, demonstrated association of M. furfur subtypes with the origin of the strain (skin or systemic isolate), whereas PCR-fingerprinting of the mini-satellite DNA clustered M. furfur strains according to their geographic origin and disease origin. Moreover, much typing work has already been performed regarding the zoophilic species M. pachydermatis and the relevant methods can be adapted for studying the anthropophilic Malassezia species. In the near future, molecular typing will be a powerful tool in epidemiological studies that could be employed for the elucidation of the pathobiology of Malassezia species in associated skin diseases.