Generally, skin properties are highly specific for each individual depending on various factors such as genetic predisposition, age, gender, body region, health and lifestyle. In this study, we measured various skin parameters on forehead, temple and cheek of 442 Caucasian women between 23 and 63 years, and evaluated differences between these facial regions and also the relationship between skin parameters and age of the volunteers. We measured transepidermal water loss (TEWL), stratum corneum hydration, skin gloss, melanin level, individual typology angle (ITA), erythema, sebum level and elasticity (R7). We observed significant negative relationship between age and TEWL, elasticity and skin lightness represented by ITA. Sebum, melanin and erythema levels increased up to the age of 50, when menopause usually takes place, and then decreased again. Evaluating the skin parameters on the forehead, temple and cheek area, we observed the biggest differences between the cheek and the forehead. The cheek possessed the worst skin parameters, such as the highest TEWL and erythema values and the lowest hydration.

Background The human skin is greatly affected by external factors such as UV radiation (UVR), ambient temperature (T), and air humidity. These factors oscillate during the year giving rise to the seasonal variations in the skin properties. The aim of this study was to evaluate the effect of seasons, environmental T, relative and absolute humidity on the skin parameters of Caucasian women, perform a literature review and discuss the possible factors lying behind the found changes. Materials and Methods We measured stratum corneum (SC) hydration, transepidermal water loss (TEWL), sebum level, erythema index, and elasticity parameters R2 and R7 on the forehead and the cheek of Caucasian women from the Czech Republic throughout the year. We also performed a non‐systematic literature review focused on the seasonal variations in these skin parameters. Results We confirmed a well‐documented low SC hydration and sebum production in winter. In spring, we found the lowest TEWL (on the forehead) and the highest SC hydration but also the highest erythema index and the lowest elasticity presumably indicating skin photodamage. For most of the skin parameters, the seasonal variations probably arise due to a complex action of different factors as we extensively discussed. Conclusion The data about the seasonal variations in the skin parameters are still highly inconsistent and further studies are needed for better understanding of the normal skin changes throughout the year.

Senile skin atrophy is a common side eff ect of intrinsic aging and UV exposition and it aff ects both dermal and epidermal layers of the skin. While dermal atrophy is mostly associated with the loss of connective tissue, epidermal atrophy manifests as overall thinning of epidermis, reduction of keratinocyte size and fl attening of the dermoepidermal junction. Compared to senile atrophy, steroid skin atrophy frequently arises during glucocorticoid therapy and causes serious skin damages, particularly when applied to fragile skin.

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Hemidesmosomes (Scheme I) are the specialized protein complexes present in the basement membrane, where they help to attach the epidermal cells to basal lamina. They are the key components ensuring skin integrity and thus, they contribute to the maintaining of the skin homeostasis. They consist of several distinct proteins, such as α and β integrins, CD151, plectin, collagen 17A1 and dystonin. During skin ageing and photoageing, the number of hemidesmosomes decreases. Therefore, the skin barrier function impairs and the skin become more fragile 1,2 . However, no study evaluating the hemidesmosomal proteins levels during ageing has been carried out so far.