Skin microbiome

The skin microbiome is a complex ecosystem of microorganisms inhabiting the surface of human skin. It includes bacteria, fungi, viruses, and mites, which remain in dynamic equilibrium with the host organism. Modern dermatology recognizes the microbiome as one of the key elements of the skin's protective barrier, influencing local immunity, inflammatory processes, hydration, and the rate of tissue aging. A properly functioning microbiome supports the integrity of the epidermis, limits the proliferation of pathogenic microorganisms, and participates in the regulation of the immune response. Microbiological imbalances, referred to as dysbiosis, are associated with the development of numerous dermatological diseases, including atopic dermatitis, acne, seborrheic dermatitis, or rosacea.

Skin microbiome – which microorganisms make it up?

Human skin is an environment for billions of microorganisms, whose composition depends on age, gender, sebaceous gland activity, anatomical location, and environmental factors. The dominant group consists of bacteria belonging mainly to the genera:

Cutibacterium (formerly Propionibacterium),
Staphylococcus,
Corynebacterium,
Micrococcus.

In areas rich in sebaceous glands, lipophilic bacteria dominate, especially Cutibacterium acnes, which participate in sebum metabolism and maintaining the acidic pH of the skin. Moist areas, such as the armpits or groin, are more frequently inhabited by bacteria of the genera Corynebacterium and Staphylococcus.

Fungi, mainly of the genus Malassezia, are also an important element of the microbiome. Under physiological conditions, they remain a neutral component of the skin flora; however, their overgrowth may participate in the development of dandruff, seborrheic dermatitis, or pityriasis versicolor.

The microbiome also includes viruses, primarily bacteriophages regulating bacterial populations, and microscopic mites Demodex folliculorum, naturally residing in hair follicles.

Modern research indicates that skin microorganisms do not function randomly. They create complex biofilms and networks of metabolic dependencies, influencing:

the production of antimicrobial peptides,
the integrity of the hydrolipid barrier,
the regulation of inflammation,
epidermal regeneration processes.

Skin microbiome – how does it change with age?

The composition of the skin microbiome undergoes significant changes at various stages of life. Already during birth, the first colonization of the newborn's skin occurs by microorganisms originating from the mother and the external environment. The mode of delivery affects the initial composition of the microbiota – children born naturally show greater diversity of microorganisms than newborns after a cesarean section.

During infancy, the microbiome remains unstable and matures dynamically along with the development of the immune system. During hormonal puberty, increased activity of the sebaceous glands leads to the intensive proliferation of lipophilic bacteria, particularly Cutibacterium acnes. This phenomenon plays an important role in the pathogenesis of acne.

In adulthood, the microbiome reaches relative stability, however its composition still remains susceptible to the influence of the environment, diet, stress, and skincare.

The skin aging process, on the other hand, is associated with:

a decrease in the diversity of microorganisms,
weakening of the hydrolipid barrier,
a reduction in sebum secretion,
a decline in the skin's immunological activity.

In elderly people, more frequent microbiological imbalances are observed, which favors chronic inflammation, hypersensitivity, and slower regeneration of the epidermis. More and more studies also indicate a link between the aging of the microbiome and the phenomenon of so-called inflammaging, i.e., a chronic low-grade inflammation that accelerates tissue aging processes.

Skin microbiome – what disrupts its balance?

Skin microbiological balance remains exceptionally sensitive to the effects of external and internal factors. Dysbiosis can lead to a weakening of the skin's protective barrier and an increase in susceptibility to dermatological diseases.

The most important factors disrupting the microbiome include:

Excessive hygiene and aggressive care

Washing the skin too frequently, using strong detergents, alcohol, and cosmetics with a high potential for irritation leads to damage of the hydrolipid layer and the elimination of beneficial microorganisms.

Antibiotic therapy

Topical and systemic antibiotics reduce the number of both pathogenic bacteria and physiological protective microflora. Long-term antibiotic therapy may promote the selection of resistant strains and chronic microbiome disorders.

UV radiation and environmental pollution

Smog, heavy metals, and ultraviolet radiation intensify oxidative stress, leading to changes in the skin's microbiological composition and chronic micro-inflammation.

Stress and hormonal disorders

Chronic stress increases the secretion of cortisol and inflammatory mediators, which affects the functioning of the skin barrier and the activity of microorganisms. Hormonal fluctuations can also disrupt microbiological balance.

Improper diet

A diet rich in highly processed food, simple sugars, and trans fats adversely affects both the gut and skin microbiome. More and more research indicates a close relationship between the gut–skin axis.

Skin microbiome – how to protect and support it?

Supporting the skin microbiome is currently one of the most important directions in modern dermatology and cosmetology. The goal of skin care should be not only cleansing the skin but also maintaining its biological balance.

The following are of fundamental importance:

gentle cleansing agents with physiological pH,
limiting excessive exfoliation,
regular skin moisturizing,
sun protection,
avoiding unjustified antibiotic therapy.

Cosmetics containing the following are playing an increasingly important role:

prebiotics - substances supporting the growth of beneficial bacteria,
probiotics - live microorganisms or their fragments,
postbiotics - bacterial metabolites with anti-inflammatory and regenerative effects.

In aesthetic dermatology, procedures that strengthen the epidermal barrier and limit chronic skin inflammation are of particular importance. In clinical practice, the following are used, among others:

regenerative treatments and those restoring the hydrolipid barrier,
therapies soothing skin inflammation,
mesotherapy supporting skin repair functions,
biostimulating procedures improving skin quality,
individually selected therapies for sensitive and atopic skin.

The offer includes, among others, skin regenerating treatments, anti-inflammatory therapies, procedures supporting the restoration of the hydrolipid barrier, and modern care programs aimed at improving the quality and resilience of the skin.