# Role of Nutribiotics in Skin Care
## 4 Skin Microbiome and Dermatological Disorders
Democak follicularorum is found to be implicated in rosacea; still, Demodox is unlikely to be the only cutaneous microorganism that contributes to the disease since Demodex mites are suspected of carrying _Bacillus oleeronius_, a pro-inflammatory Gram-negative bacterium that is receptive to many antibiotics recurrently used to treat rosacea [82], resulting in an amelioration of the disease when treating it with antibiotics. The origin of rosacea development is unclear, but several factors are involved, including genetic factors, local skin immune imbalance, disorders of autoimmune function, skin barrier dysfunction, and skin microbiota dysbiosis, as well as alterations in neurovascular circuitry [123]. The role of the microbiota in rosacea pathogenesis is supported by several sources. Studies conducted by different authors have pointed to the implication of _Staphylococcus epidermidis_, _Demodex follicularorum_, _Helicobacter pylori_, _Bacillus oleeronius_, and _Chlamydia pneumonia_ in the pathogenesis of rosacea [95; 96; 97; 98; 99]. However, there are discrepancies between the results of these investigations and the specific mechanisms by which the microorganisms are involved in the pathogenesis of rosacea are not clear as they are commensal microorganisms. More specifically, the distribution, relative abundance, mechanisms involved, and thus the role of _Cutibacterium acnes_ and _S. epidermidis_ in rosacea need to be further investigated to provide evidence for future probiotic therapy [124]. Finally, the aforementioned review by [PERSON] and [PERSON] [89] described that, in papulopustular rosacea, the proportions of _Firmicutes_ and _Proteobacteria_ are higher and _Actinobacteria_ proportions are lower. Seborrheic dermatitis (SD) is an inflammatory rash that appears on sebaceous areas of skin, such as the scalp, face, and trunk [102]. The incidence of SD reaches the highest point at three ages of life--infancy, puberty, and in adults over 50 years old--suggesting the role of hormones in sebum production in its pathogenesis [45]. SD is generally associated with Malassezia; however, its role in the development of SD is still poorly understood [100]. Some studies suggest that there are other microorganisms involved. For example, [PERSON] et al. [101] found that Acinetobacter, Staphylococcus, and Streptococcus are the dominant genera on the skin microbiome of lesional areas affected with SD compared to healthy skin; [PERSON] et al. [102] found that patients with SD have a significant over-colonization of _Staphylococcus epidermidis_, concluding that this high colonization along with alteration of the skin barrier function, which is more permeable, contributes to the appearance of SD. Dandruff, considered a form of middle seborrheic dermatitis, has also been found to be linked to Malassezia. A study performed by [PERSON] et al. [103], using molecular techniques, showed increased colonization of _Malassezia restricts_ and of Staphylococcus species when compared to healthy scalps. Other skin disorders have also been associated with skin microbiome dysbiosis. Hidradenitis suppurativa was found to be linked to the dermal microbiota as the microbial composition differs significantly from that of healthy individuals. Overall, the following five types of microbes were identified: _Corynebacterium_ spp. (type I), _Acinetobacter_ and _Monaxella_ spp. (type II), _Staphylococcus epidermidis_ (type III), _Peptioniphilus_ spp. and _Porphyomonas_ (type IV), and _Propioniibacterium acnes_ (type V), suggesting that Propionibacterium may be involved on its pathogenesis [104]. Tinea pedis is a dermatophyte infection that especially affects the interdigital network and/or the sides of the feet. Different factors have been found that may be related to its appearance, such as sweating, occlusive footwear, trauma, and an immunocompromised state, among others.