Senile xerosis: what should we know about this age-related skin dryness?

Senile xerosis is the scientific term for a significant skin dryness associated with the skin ageing process. This term originates from Greek, where "xeros" means "dry" and "osis" refers to a disorder or disease. The dry skin observed in older individuals stems from the deterioration of the skin barrier that occurs over time. Indeed, with age, the skin undergoes structural and functional changes that impair its ability to retain water and protect itself from external aggressions. Several biological mechanisms are involved and help explain the onset of xerosis.

Firstly, we can mention the gradual decrease in the production of epidermal lipids, particularly ceramides, cholesterol, and free fatty acids, which significantly impairs the skin barrier function. Indeed, intercellular lipids are essential for maintaining skin hydration by forming lamellar bilayers in the stratum corneum, the outermost part of the epidermis. Their organisation into ordered structures allows for the trapping of water within the epidermis and limits insensible water loss.

Furthermore, the natural moisturising factor (NMF) sees its concentration decrease with age. As its name suggests, it is essential for skin hydration. Present within the corneocytes of the stratum corneum, the natural moisturising factor is mainly composed of amino acids, their derivatives and other hygroscopic molecules capable of attracting and retaining water. Its decrease accentuates transepidermal water loss (TEWL), a phenomenon further exacerbated by the decrease in sebum production by the sebaceous glands observed during skin ageing. Indeed, a decrease in sebum is accompanied by a weakening of the hydrolipidic film, of which it is an essential element. As a reminder, the hydrolipidic film is a protective veil covering the epidermis that both prevents the penetration of pathogens into the skin and limits the evaporation of water.

Over time, the reduction of lipids in the stratum corneum, the natural moisturising factor, and sebum production weakens the skin barrier, promoting the onset of xerosis.

As specified above, senile xerosis manifests as an intense skin dryness. While it can affect the entire body, it is more common on the arms and legs and is recognised by various symptoms:

• Feelings of tightness and discomfort.

  Senile xerosis, or dry skin, is first and foremost recognised by the feeling of tight and uncomfortable skin it causes. This phenomenon is particularly noticeable after showering, where the rapid evaporation of water exacerbates skin dehydration, leaving a feeling of tightness. Furthermore, the skin, less flexible, seems to lose elasticity and can feel rigid. In addition to this tension, tingling and increased sensitivity may occur, particularly in response to temperature changes or certain irritating fabrics. This is due to the deterioration of the skin barrier, which exposes nerve endings more to external aggressions.

• Irritations and a skin that flakes.

  Senile xerosis can also manifest itself through redness and flaking of the epidermis. Deprived of its natural hydration and protection, the skin becomes more reactive and is more prone to irritations, whether it's sudden changes in temperature, pollution or the use of harsh products. In parallel, skin affected by xerosis tends to flake and peel off in small layers, a sign of disturbed skin regeneration. This flaking is more precisely explained by a slowdown in cell renewal. Dead cells are then no longer properly eliminated and accumulate on the surface of the skin, making it rough and giving it a "crocodile skin" appearance.

• Feelings of itchiness.

  Senile xerosis is the primary cause of itchiness in elderly individuals. This symptom should not be taken lightly as it can significantly impact quality of life and disrupt daily activities and sleep. The itchiness experienced in cases of senile xerosis is the result of an overactivation of the skin's nerve endings, exacerbated by the impairment of the skin barrier. Although easier said than done, it is important to try as much as possible not to scratch. Indeed, repeatedly scratching an area can worsen xerosis and cause lesions which, by facilitating the entry of pathogens, increase the risk of infections.

Senile xerosis can be effectively managed through the use of moisturising and nourishing creams. For optimal effectiveness, it is recommended to choose treatments that contain a combination of humectants, film-forming agents, and emollients, in order to compensate for the lack of lipids and improve the skin's hydration and barrier function. Indeed, scientists agree that a combination of hydrophilic and lipophilic molecules is preferable. A study conducted by MICALI and his team examined the effectiveness of a cream containing, among other things, 10% urea to manage the xerosis of 20 patients aged 65 and over.

A four-level clinical severity score was used to assess skin dryness (0 = normal skin; 1 = mild xerosis; 2 = moderate xerosis; 3 = severe xerosis). Pruritus was also measured using a four-level severity scale (0 = no pruritus; 1 = mild pruritus, 2 = moderate pruritus; 3 = severe pruritus). These parameters were observed at the start of the study and then 7 and 14 days after daily application of the cream. A clear improvement in these two factors and in the participants' xerosis was observed.

This study is not an isolated case. Several pieces of research have demonstrated that the regular and long-term application of a moisturising and nourishing treatment can alleviate senile xerosis. At Typology, we offer a lipid-replenishing balm, designed for dry to very dry skin, providing continuous hydration for 24 hours and allowing for extended periods between severe dryness. This treatment notably contains ceramides, shea butter and camelina oil, which help to restore the intercellular cement of the epidermis and the skin barrier, as well as an extract of Ophiopogon Japonicus roots, which have moisturising and anti-inflammatory properties.

• ROBERTS M. S. & al. Skin biology, dry skin, barrier restoration and measurement. Drug Discovery Today: Disease Mechanisms (2008).

• 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).

• ZIEMER C. & al. Dry Skin in the Ageing Population: A Method for Diagnosis and Treatment. Current Geriatrics Reports (2020).

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

• MICALI G. & al. 10% urea cream in age-related xerosis: Clinical and instrumental evaluation. Journal of Cosmetic Dermatology (2021).