Many relatively common chronic inflammatory skin diseases manifest on the face (seborrheic dermatitis, rosacea, acne, perioral/periorificial dermatitis, periocular dermatitis, etc.), thereby significantly impairing patient appearance and quality of life. Given the yet unexplained pathogenesis and numerous factors involved, these diseases often present therapeutic challenges. The term “microbiome” comprises the totality of microorganisms (microbiota), their genomes, and environmental factors in a particular environment. Changes in human skin microbiota composition and/or functionality are believed to trigger immune dysregulation, and consequently an inflammatory response, thereby playing a potentially significant role in the clinical manifestations and treatment of these diseases. Although cultivation methods have traditionally been used in studies of bacterial microbiome species, a large number of bacterial strains cannot be grown in the laboratory. Since standard culture-dependent methods detect fewer than 1% of all bacterial species, a metagenomic approach could be used to detect bacteria that cannot be cultivated. The skin microbiome exhibits spatial distribution associated with the microenvironment (sebaceous, moist, and dry areas). However, although disturbance of the skin microbiome can lead to a number of pathological conditions and diseases, it is still not clear whether skin diseases result from change in the microbiome or cause such a change. Thus far, the skin microbiome has been studied in atopic dermatitis, seborrheic dermatitis, psoriasis, acne, and rosacea. Studies on the possible association between changes in the microbiome and their association with skin diseases have improved the understanding of disease development, diagnostics, and therapeutics. The identification of the bacterial markers associated with particular inflammatory skin diseases would significantly accelerate the diagnostics and reduce treatment costs. Microbiota research and determination could facilitate the identification of potential causes of skin diseases that cannot be detected by simpler methods, thereby contributing to the design and development of more effective therapies.

Melatonin is the main hormone that regulates the sleep cycle, and it is mostly produced by the pineal gland from the amino acid tryptophan. It has cytoprotective, immunomodulatory, and anti-apoptotic effects. Melatonin is also one of the most powerful natural antioxidants, directly acting on free radicals and the intracellular antioxidant enzyme system. Furthermore, it participates in antitumor activity, hypopigmentation processes in hyperpigmentary disorders, anti-inflammatory, and immunomodulating activity in inflammatory dermatoses, maintaining the integrity of the epidermal barrier and thermoregulation of the body. Due predominantly to its positive influence on sleep, melatonin can be used in the treatment of sleep disturbances for those with chronic allergic diseases accompanied by intensive itching (such as atopic dermatitis and chronic spontaneous urticaria). According to the literature data, there are also many proven uses for melatonin in photoprotection and skin aging (due to melatonin’s antioxidant effects and role in preventing damage due to DNA repair mechanisms), hyperpigmentary disorders (e.g., melasma) and scalp diseases (such as androgenic alopecia and telogen effluvium).

Background: Atopic dermatitis (AD) patients commonly experience psychological stress and impaired psychosocial functioning.Objective: The aim of this study was to compare patients' salivary cortisol levels with AD severity and other associated stress-related psychological measures/parameters.Methods: This prospective study analyzed salivary cortisol levels (enzyme-linked immunosorbent assay) in 84 AD patients (42 symptomatic patients and 42 asymptomatic patients). Each subject filled out the Perceived Stress Scale (PSS), Brief Illness Perception Questionnaire, and the Crown-Crisp Experiential Index, which concerns personality features.Results: Increased cortisol values were found in both groups and were not dependent on disease severity (Scoring Atopic Dermatitis [SCORAD]) and PSS. Patients with severe AD had significantly lower cortisol levels than those with moderate and mild AD ( P = 0.042). The PSS levels were not dependent on SCORAD but correlated with the perceived effect of AD on emotional states (Illness Perception Questionnaire 8), personality traits, anxiety, and depression ( P < 0.001).Conclusions: The severity of perceived stress in AD patients is not adequately measured by salivary cortisol levels nor SCORAD; it does, however, correlate with the impact of AD on patients' emotional states and personality features (anxiety, depression). All AD patients, regardless of disease severity, should be assessed for impacts of stress, and a multidisciplinary approach should address mental wellness.