Your skin type refers to how your skin looks, feels and behaves, according to Paula Begoun, author of "The Original Beauty Bible." Many factors, internal and external, can influence skin type--oily, dry, sensitive--and skin condition. In addition, your skin changes as you grow older, from season to season and when get a sunburn or spend a lot of time in water. One other skin change that you may notice is thinness, which can be due to several factors.
Genes that you inherit from your parents influence your skin type, including how you age and react to certain stimuli. While you can change some factors that affect the appearance of your skin, there's not much you can do about your genetic makeup.
Too much sun exposure is the leading cause of premature aging, which changes your skin in several ways, including making it thinner. The sun's ultraviolet rays break down components in the skin---collagen and elastin---that give it its structure and elasticity, according to the American Academy of Dermatology. It also inhibits collagen production. Sitting with your arms exposed in the sun for a long period will make the skin more susceptible to thinning.
Other Environmental Factors
Other environmental factors that can thin your skin include pollution, which increases free radical activity in the body that damages collagen and DNA, states Begoun. Dry weather and secondhand smoke can also make skin thinner.
According to the Mayo Clinic, thin skin is common as you age because your skin is robbed of some of its protective fatty layer. Besides genetics and sun damage, other factors that contribute to aging include poor diet and illness.
These products are usually prescribed to treat conditions such as psoriasis and eczema, which are skin conditions that cause dryness, itching, irritation and flakiness. If you've been using these creams for a prolonged period on your lower arms to treat these conditions, it's not unusual for your skin to become thinner.
Cigarette smoking also causes premature aging and skin damage. It increases free radical activity in the body, decreases oxygen supply to your skin and other parts of your body and breaks down collagen and elastin. According to the Mayo Clinic, smoking is also linked to increased skin damage in the inner arms.