Keratin is a form of protein that forms the basis for your hair and also plays an important role in the formation of your nails and skin. Abnormalities in the keratin cells in your skin can trigger the onset of a group of disorders called keratoses. The seriousness of the different forms of keratosis ranges from cosmetic annoyance to a warning sign for the potential development of life-threatening skin cancer.
The outer layer of your skin, called the epidermis, produces keratin in several layers of specialized cells called keratinocytes, according to National Geographic. Keratinocytes give your skin its protective abilities, allowing for the simultaneous blocking of foreign substances and retention of important cellular components in your body, the American Academy of Dermatology notes. In addition to skin, keratinocytes form the basis for the mucous membranes that protect areas of your body such as your eyelids, mouth and throat.
Keratosis pilaris is a common skin condition that occurs when keratin plugs form in the openings of your hair follicles, according to The Merck Manuals Online Medical Library. This intrusion creates small, solid bumps called papules, which tend to appear on your thighs, upper arms or buttocks. Children or adults may also develop keratosis papules on their faces. Most of the impact of keratosis pilaris is cosmetic, although in some cases you may develop itchy skin or pus-filled bumps called pustules. When treatment is necessary, potential options include topical applications of petrolatum, salicylic acid, buffered lactic acid and urea.
Seborrheic keratosis is a disorder characterized by the formation of wart-like or waxy skin growths, according to the Mayo Clinic. These growths occur in sizes that range from tiny dots to lesions more than an inch in diameter, and have colors that range from black or brown to light tan or yellow. Common locations for the disorder include your shoulders, face, back and chest. Although seborrheic keratosis is a benign condition, it can closely mimic the appearance of skin cancer, the Mayo Clinic explains. You should see your doctor if you develop numerous growths in a short period of time, or if you develop bleeding or other suspicious skin changes.
Actinic keratosis is a skin condition caused by long-term sun exposure, the American Academy of Dermatology reports. Actinic lesions range in size from tiny dots to areas larger than a quarter, have a scaly or roughened texture, and have colors that range from flesh tone to reddish brown. Common locations for these growths include your ears, lips, face, forearms, neck, scalp and the backs of your hands. Doctors consider actinic keratosis a precursor for the development of skin cancer, and if you have actinic lesions, you should have your skin checked regularly for dangerous changes.
The American Academy of Dermatology lists methods of preventing actinic keratosis and skin cancer that include avoiding purposeful tanning, limiting everyday sun exposure, regularly using sunscreen and wearing clothing that diminishes sun exposure. You should also be aware of surfaces that can amplify harmful sun effects, including snow, sand and water.