Inflammatory reactions of the skin


When your skin’s microbiome is out of balance, inflammatory diseases such as acne, eczema and dandruff can occur. Discover how the skin reacts to the presence of certain bacteria.


Acne is caused by a disruption of the bacterial population on the skin. Hormonal changes during puberty or at a later age with women may stimulate the growth of Propionibacterium. It’s a naturally occurring and perfectly harmless bacterium that we all have, the problem of acne only occurs when the bacterium overgrows.

Hair follicles contain sebaceous glands that produce sebum. Sebum keeps our hair and skin moisturised, protecting us from dehydration. Propionibacterium acnes lives within these sebaceous glands. The bacterium feeds on the fatty acids in the sebum so the more sebum you produce, the more the microorganisms are able to grow. Overproduction of sebum can happen because of hormonal changes during puberty or the menopause.

As Propionibacterium acnes also proliferates easily in a low oxygen environment, you want to make sure that your pores are able to ‘breathe’. When sebum and dead skin cells clog the hair shaft, there is less oxygen, which stimulates the growth of Propionibacterium acnes.

It’s this excessive production of Propionibacterium acnes that causes an inflammatory reaction of the immune system: a spot appears. The presence of Staphylococcus aureus – another naturally occurring bacterium – could exacerbate this local inflammation as well.


Eczema is a superficial infection of the skin. It results from a combination of genetic and environmental factors that affect the skin. But also the aforementioned Staphylococcus aureus bacterium is also involved in the development of eczema. Studies show that the bacterium produces a biofilm that blocks sweat glands. This activates a molecule that causes a reaction at the level of immune system cells. The cells release small granules that cause inflammation, itching and irritation.


When the process of cell renewal of the scalp accelerates, corneal cells will multiply faster. This peeling process is called dandruff. The fungus Malassezia globosa or Pityrosporum ovale lives in the sebum produced by the sebaceous glands of the hair follicles and causes this excessive multiplication of cells. The microorganism irritates the scalp and causes an inflammatory reaction. Genetic predisposition, climate, stress, hormonal changes and lifestyle can also influence this process.

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