The role of skin microbiome in the development of atopic dermatitis in children

Atopic dermatitis is a chronic itchy skin disease with a characteristic localization and morphology of skin lesions associated with an impairment of the skin barrier function and an atopic background. Malassezia species have been associated with a number of skin conditions, including atopic dermatitis. It is the most common fungal genus of healthy skin, but this yeast also may have a pathogenic potential under certain conditions. A close relationship has been shown between skin and Malassezia allergens that bind IgE in atopic dermatitis. They interact with almost all cellular constituents of the normal epidermis, including keratinocytes, Langerhans cells, melanocytes, and the host’s immune system. It is known that Malassezia yeasts are of great importance in the development of skin sensitization in atopic dermatitis. Ma­lassezia colonize human skin after birth and therefore, as a commensal, should be normally recognized by the human immune system. The presence of polymorphisms in the PRR genes can cause the development of atopic dermatitis in children. Despite the current knowledge about the association of Malassezia species with the development of atopic dermatitis, the mechanisms underlying the change in their state from commensal to pathogenic still require further elucidation. In addition, there is a need for standardization of diagnostic methods and testing for antifungal susceptibility.