Too many pigment cells

Aged skin, especially in light skin types, is characterized brown, flat and raised areas of pigment. These can be solar lentigos as seen in this leg and face photo

A lentigos is a small, pigmented spot on the skin surrounded by normal skin. Its borders are distinct and the color is consistent throughout the lentigos. Lentigos caused by the sun are called solar lentigos. These often appear on the face and arms. Comparing the lentigos of the sun-exposed side of the arm to the even-toned skin of the side shielded from the sun is a good way to gauge how much sun exposure someone has had. Lentigos are caused by an increased number of pigment-producing cells known as melanocytes. They are not the same thing as freckles.

Solar lentigos are harmless and must be distinguished from melanomas, which are deadly and should be removed as soon as possible to increase survival rates. Melanomas occur when the melanocytes become cancerous and proliferate rapidly. They can metastasize throughout the body, which is what makes them so dangerous. Both solar lentigos and melanomas occur after sunburns and increased sun exposure. An increased number of solar lentigos may be associated with an increased risk of melanoma. If you have solar lentigos it is advised that a dermatologist check your skin every year. If you have had melanoma in the past or if a parent or sibling has melanoma, you should be checked every 6 months.

Melanoma has indistinct borders and irregular color as seen in the picture below.

Click here to learn how to spot melanoma.

Too many outer skin layer cells

Aged skin is thinner in the dermis; however, the top layer (the epidermis) is often thickened. This thickening is caused by too many keratinocyte cells in the stratum corneum (SC), which is the very top layer of the skin’s surface. This occurs because the keratinocytes normally migrate towards the skin’s surface, and as the keratinocytes die, they accumulate at the surface of the skin. Normally, naturally occurring enzymes degrade the connections between the SC cells, releasing them from the cells below, which allows them flake off (desquamate) away from the skin. Older, aged skin lacks these enzymes. This leads to a buildup of dead skin cells on the surface of the skin. This buildup makes the skin look sallow and prevents the skin from reflecting light. People often complain that the skin looks “dull and tired.” Cosmetic products can be used to make the skin look smoother and more radiant. This video will further explain this process.

Too many keratinocyte or fibroblast skin cells

The epidermis of the skin is composed of cells known as keratinocytes. Keratinocytes can become cancerous and began to replicate and produce many copies of themselves. When the superficial keratinocyte cells become cancerous, it is known as squamous cell carcinoma, or SCC. When the deeper, or basal, keratinocytes become cancerous, this is known as basal cell carcinoma, or BCC. SCCs and BCCs are more common in people with a history of a significant amount of sun exposure. SCCs and BCCs are usually treated surgically which can lead to scarring.

Click here to learn more about skin cancer.

If you have any lesions on your skin that grow rapidly or that seem to become scabs that do not heal, please see your dermatologist. A board-certified dermatologist in your area can be found at http://www.AAD.org.

We hope that you enjoyed our second installment in our series about “The 7 Causes of Aging.” Stay tuned for next week when we’ll discuss “Protein crosslinks” as a cause of aging. The protein crosslinks discussion will explain glycation and skin care products that claim to prevent this aging process.