In addition to gender issues, age issues are also important to the formulator. Newborn children produce little sebum and eccrine sweat. Sebum production typically does not begin until the hormonal changes of puberty occur, as discussed previously; thus, most children have dry skin. This creates a challenge, since children frequently get their skin dirty, which necessitates washing. The child may not produce enough sebum to combat the effect of cleansing that may remove the intercellular lipids resulting in barrier damage. This creates the need for thorough mild cleansers and moisturizers for children. Careful formulation is essential, since the skin of children is also thin and their well-functioning immune system is likely to respond aggressively to irritants and allergens. It is for this reason that children are considered to have sensitive skin.
Puberty brings full functioning of the sebaceous, apocrine, and eccrine glands. This may be advantageous to dry skinned children who will no longer suffer from eczema. Many times allergies also become attenuated at this age. But, of course, oil, and sweat removal become more of a problem as acne and body odor emerge. The next complexion change generally occurs around age 40 as sebum production begins to decline. There is great variability in the age at which sebum production changes. In women, dramatically
decreased sebum production occurs at menopause, which usually begins by age 50 and is completed by age 60.
Usually about age 60 there is a transition in both men and women to geriatric skin. While this is not a proper medical term, there are unique skin needs of the elderly. These include skin fragility that results in easy skin tears and bruising due to loss of dermal collagen, which confers the skin’s strength. Even the rubbing of thick viscous skin creams can cause bruising in elderly skin, medically known as senile purpura. Elderly skin is also unique in that it appears chronically dry, even though noninvasive skin measurements, such as transepidermal water loss, are normal. This may be due to the decreased ability of dead skin scale to slough in a timely manner. The buildup of corneocytes appears like dry skin even though the viable epidermis is well moisturized. This means that moisturizers designed for geriatric skin should encourage desquamation and provide superior emolliency to smooth the dry-appearing corneocytes.
The last area to discuss in elderly skin is itching. Geriatric skin is uniquely itchy, even though there is little visible evidence of barrier disruption. Itching is typically due to barrier disruption, medically termed dermatitis, and lack of protection of underlying dermal nerve endings. In the elderly, severe itching may be reported even though no dermatitis is present. This is a diagnostic enigma for the dermatologist. Skin itching appears to become worse in the postmenopausal female; thus, estrogen may play a role. However, the exact cause of the itching is not always apparent. It may be due to depression, poor dermal support of the nerve endings, abnormal intercellular lipids, etc. Thus, itch reduction is a skin care need in the elderly, not frequently seen in younger populations.