Comparative analysis of skin fungal colonization in patients with atopic dermatitis and healthy individuals

Atopic dermatitis is a chronic, relapsing inflammatory skin disease. Immune dysregulation occurs, leading to inflammation in response to allergens that penetrate through a compromised epidermal barrier. Defects in the skin barrier and inflammatory processes in the skin result in increased colonization by conditionally pathogenic microorganisms. Fungal microbiota dysbiosis (Malassezia spp. and others) is considered one of the factors involved in the pathogenesis of atopic dermatitis. However, the influence of fungal microflora on atopic dermatitis remains less studied compared to the role of bacterial microorganisms. The aim of this study was to conduct a comparative analysis of the prevalence of fungi in patients with atopic dermatitis and a control group using real-time polymerase chain reaction. The study included 151 participants. The group of patients with atopic dermatitis included lesions from different locations, and for more accurate comparison. The control group was formed considering both dry skin areas and areas with increased sebum production. All patients had their diagnosis of atopic dermatitis confirmed according to clinical guidelines. Disease severity was assessed using the SCORAD index. Epithelial scrapings were collected depending on lesion location. The obtained skin samples were analyzed using real-time PCR. It was found that patients with atopic dermatitis exhibited significantly higher levels of fungal colonization compared to the control group. Specifically, patients with atopic dermatitis more frequently harbored various yeast species such as Candida, Malassezia, and Saccharomyces cerevisiae, as well as non-dermatophyte molds like Aspergillus spp./Penicillium spp. Additionally, we observed that the distribution of Candida and Malassezia restricta species varies depending on the severity of atopic dermatitis. Changes in the fungal composition of the skin play an important role in the pathogenesis of atopic dermatitis, potentially activating the immune system and exacerbating inflammatory processes. Although fungi are not direct causative agents of atopic dermatitis, an imbalance in their populations likely contributes to disease exacerbation and progression. Further research is needed to better understand how fungi influence atopic dermatitis development particularly studies focusing on immune responses to fungi and allergy mechanisms related to their alterations. Such data could aid in developing new therapeutic and preventive strategies for this condition.

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