Clinicopathological differentiation between Pityrosporum folliculitis and acneiform eruption

Position statement: Recommendations on the diagnosis and treatment of Malassezia folliculitis

Malassezia is a lipophilic yeast that is a part of the human mycobiome. Malassezia folliculitis appears when the benign colonization of the hair follicles, by the Malassezia yeasts, becomes symptomatic with pruritic papules and pustules. Although Malassezia folliculitis is common in hospital departments, diagnosing and treating it varies among dermatologists and countries. The European Academy of Dermatology and Venereology Mycology Task Force Malassezia folliculitis working group has, therefore, sought to develop these recommendations for the diagnosis and management of Malassezia folliculitis. Recommendations comprise methods for diagnosing Malassezia folliculitis, required positive findings before starting therapies and specific treatment algorithms for individuals who are immunocompetent, immunocompromised or who have compromised liver function. In conclusion, this study provides a clinical strategy for diagnosing and managing Malassezia folliculitis.

Malassezia Folliculitis in the Setting of COVID-19

Purpose of Review

To review recent literature on Malassezia folliculitis and explore its association with COVID-19.

Recent Findings

Reports of Malassezia folliculitis in the setting of COVID-19 are scarce. Shared characteristics between affected individuals include male sex, obesity, intensive care, and administration of systemic antibiotics and systemic steroids. Dexamethasone can potentially stimulate sebum production and therefore lead to Malassezia proliferation. The clinical picture of Malassezia folliculitis accompanying COVID-19 is similar to classic descriptions but tends to spare the face and predominates in occlusion sites.

Summary

Malassezia folliculitis is under-recognized. Fever, sweating, occlusion, immobility, antibiotics, and dexamethasone contribute to COVID-19 patients developing Malassezia folliculitis. Antifungal therapy, together with correcting predisposing factors, is the mainstay of management. Future research should explore the relationship between systemic steroids and other acneiform reactions.

[Clinical picture, causative agents and diagnostics of dermatomycoses]

Dermatomycoses affect free skin, hairy scalp, fingernails and toenails. In addition, oral mucosa and genital mucosa can also be affected by fungal infections. The most common pathogens causing skin fungal infections are dermatophytes. They are responsible for, among others, tinea corporis, tinea capitis and onychomycosis (tinea unguium). Mainly anthropophilic dermatophytes are found as pathogens. In the case of tinea capitis-at least in Europe and in German-speaking countries-zoophilic skin fungi must also be considered. Rarely, geophilic dermatophytes can also be isolated. Yeast infections of the skin, mostly caused by Candida albicans, primarily affect the intertriginous skin areas, for example, the groin region, but also the submammary area and the spaces between the fingers and toes. Elderly patients are often affected, but also infants and, in particular, immunocompromised patients. These patient groups are also more frequently affected by oral mucosal infections caused by Candida albicans and other Candida species. Pseudomembranous candidiasis of the oral mucosa and tongue typically affects patients with HIV/AIDS. Mold infections in dermatology are relevant in onychomycosis of the big toenail. The causative agent is usually Scopulariopsis brevicaulis. Cutaneous mold infections are rare and only occur in immunocompromised patients. The mycological diagnosis of dermatomycoses is based on the microscopic, if possible fluorescence-optical detection of fungal hyphae and spores from skin scales, nail shavings and hair roots. The culture detection of dermatophytes, yeasts and molds allows the identification of the causative fungal species, but often fails, especially in patients who have already been treated with antifungal agents. In view of the high sensitivity and specificity of the molecular methods for fungal detection compared to culture, polymerase chain reaction (PCR) must realistically be regarded as the gold standard for dermatophytosis diagnostics. However, it should not be neglected that the three pillars of diagnostics-preparation, culture, PCR-currently deliver the best results.

Malassezia-Associated Skin Diseases, the Use of Diagnostics and Treatment

Yeasts of the genus, Malassezia, formerly known as Pityrosporum, are lipophilic yeasts, which are a part of the normal skin flora (microbiome). Malassezia colonize the human skin after birth and must therefore, as commensals, be normally tolerated by the human immune system. The Malassezia yeasts also have a pathogenic potential where they can, under appropriate conditions, invade the stratum corneum and interact with the host immune system, both directly but also through chemical mediators. The species distribution on the skin and the pathogenetic potential of the yeast varies between different Malassezia related diseases such as head and neck dermatitis, seborrheic dermatitis, pityriasis versicolor, and Malassezia folliculitis. The diagnostic methods used to confirm the presence of Malassezia yeasts include direct microcopy, culture based methods (often a combination of morphological features of the isolate combined with biochemical test), molecular based methods such as Polymerase Chain Reaction techniques, and Matrix Assisted Laser Desorption/Ionization—Time Of Flight mass spectrometry and the chemical imprint method Raman spectroscopy. Skin diseases caused by Malassezia are usually treated with antifungal therapy and if there are associated inflammatory skin mechanisms this is often supplemented by anti-inflammatory therapy. The aim of this paper is to provide an overview of Malassezia related skin disease, diagnostic methods and treatment options.