What are the consequences of xerosis?

The xerosis, that is to say extreme skin dryness, results from a dysfunction of the skin barrier, which can no longer effectively retain water or protect itself from external aggressions. Normally, the skin maintains its hydration through a balance between the lipids in the epidermis, the hydrolipidic film and the natural moisturising factor (NMF), referring to all the hygroscopic substances responsible for maintaining hydration in the stratum corneum. When an imbalance occurs and its barrier function no longer effectively fulfils its role, the skin becomes more reactive to environmental stimuli, which can lead to more or less significant biological repercussions if the xerosis is not properly managed.

• An acceleration of skin ageing.

  Dry skin naturally tends to age faster than oily skin. This tendency is even more pronounced for those suffering from xerosis. Indeed, a more fragile skin barrier results in a epidermis more exposed to external aggressions, including UV rays, the primary cause of skin ageing. These act at different levels of the skin, notably by generating free radicals. Several studies have confirmed that UV rays produce enough free radicals to overwhelm the skin's endogenous antioxidant defences. They also play a role in the UVA-dependent induction of matrix metalloproteinases and promote the degradation of the dermis' protein fibres, resulting in skin that is less firm, less elastic, and less supple.

  Furthermore, without adequate internal hydration, the skin tends to show more signs of ageing. Indeed, when skin suffers from xerosis, water evaporates more rapidly and more intensely than under normal conditions. This skin dehydration manifests itself through the appearance of small grooves, the dehydration fine lines, particularly around the eye and lip contours, which are already delicate areas.

• Chronic inflammation and an increased risk of dermatoses.

  In instances of prolonged xerosis, the skin becomes more reactive and more prone to persistent inflammation. Indeed, when deprived of its hydration, the skin barrier deteriorates, allowing irritants, allergens, and microorganisms to penetrate more easily. This vulnerability can result in a hyperactivation of the immune system and chronic inflammation, resembling a eczema, with redness, tightness, and itching. Similarly, psoriasis, a dermatosis based on an accelerated renewal of skin cells, is more likely to occur when the skin is affected by xerosis.

• A favourable environment for skin infections.

  Dry and weakened skin provides an ideal entry point for pathogens. Normally, the epidermis acts as a shield against bacteria, viruses, and fungi, thanks to a well-organised lipid structure and the presence of certain antimicrobial peptides, such as defensins and cathelicidins. However, in the case of xerosis, this protection weakens and the stratum corneum becomes more permeable, which facilitates the infiltration of microorganisms.

  Bacterial infections then become more frequent, particularly those caused by Staphylococcus aureus. This bacterium, naturally present on the skin, can then proliferate and cause infections such as impetigo or folliculitis. Fungi, especially those of the genus Candida or Malassezia, also take advantage of a weakened skin barrier to colonise the skin and trigger fungal infections. In this context, it is better to prevent than to cure and to combat xerosis as soon as it appears.

• A deterioration in the quality of life.

  Finally, living with persistently dry and uncomfortable skin can quickly become taxing. Xerosis is not limited to a mere sensation of discomfort: it can be accompanied by redness, cracks, and especially itching, which often intensifies during the night and can disrupt sleep. In some cases, wearing tight clothing can be challenging and pain can interfere with daily activities, such as walking if the xerosis affects the heels.

  Furthermore, beyond physical sensations, xerosis can also have a psychological impact, especially if it affects a visible area of the body. Skin marked by dryness, redness or flaking can alter self-image and confidence, potentially leading to behaviours of social avoidance and self-withdrawal. If we add to this the constraints related to skin care, such as adapting one's care routine and the frequent application of emollient balms several times a day to soothe the skin, it becomes clear that xerosis is not as harmless as it may seem.

• GROVE G. & others Stratum Corneum Lipids in Skin Xerosis. Dermatologica (1989).

• GIMÉNEZ-ARNAU A. & al. Xerosis: A Dysfunction of the Epidermal Barrier. Actas Dermo-Sifiliográficas (2008).

• STAUBACH P. & al. Diagnosis and treatment of xerosis cutis – a position paper. JDDG: Journal of the German Society of Dermatology (2019).

• KOTTNER J. & al. Molecular characterisation of xerosis cutis: A systematic review. Plos One (2021).

• HOLLO P. & others. Characteristics of ageing skin, xerosis cutis and its complications. Advancements in Health Sciences (2022).