Keratin is a protein that forms the primary structural component of the outer layer of human skin, hair, and nails. It provides a protective barrier against environmental damage and infection. “Keratin deposits” refer to instances where this protein accumulates on the skin’s surface, manifesting as growths or textural changes. These accumulations often signal a disruption in the skin’s natural shedding process.
What Are Keratin Deposits and Why Do They Form?
Normally, skin cells, called keratinocytes, are produced in the deepest layer of the epidermis and migrate upwards, filling with keratin. As these cells reach the outermost layer, the stratum corneum, they flatten and are eventually shed in a continuous process. This renewal cycle takes about 30 days.
Keratin deposits form when this orderly shedding process is disrupted, causing keratin to accumulate. Factors contributing to this buildup can include clogged hair follicles, where keratin plugs the opening, or conditions that affect skin cell turnover. The exact reasons for this disruption are not always clear, but genetics can play a role, as can external factors like friction, sun exposure, and dry skin. Most keratin deposits are benign and do not pose a health risk.
Common Manifestations of Keratin Deposits
Milia are tiny, white, dome-shaped bumps, 1 to 2 millimeters in size, which commonly appear around the eyes, nose, cheeks, or chest. These are small cysts formed when keratin becomes trapped beneath the skin’s surface, and new skin grows over them. Milia are common in newborns but can affect individuals of any age.
Seborrheic keratoses are noncancerous skin growths that appear waxy, scaly, and have a “stuck-on” appearance. They can range in color from light tan to brown or black and vary in size from a millimeter to several centimeters. The precise cause is unknown, but they are more common in adults over 50 and increase with age, appearing on the face, chest, back, or scalp.
Actinic keratoses present as rough, scaly patches on sun-exposed areas such as the face, lips, ears, forearms, and backs of the hands. These growths are caused by long-term exposure to ultraviolet (UV) radiation, leading to damage to the keratinocytes. Actinic keratoses are considered precancerous, carrying a small risk of developing into squamous cell carcinoma if left untreated, around 5% to 10%.
Calluses and corns are areas of thickened, hardened skin that develop in response to repeated pressure or friction. Calluses are broader and less painful, forming on the hands or soles of the feet due to activities like using tools or walking barefoot. Corns are smaller, more concentrated areas with a central core, found on or between toes, caused by ill-fitting footwear.
Addressing and Preventing Keratin Deposits
Managing common keratin deposits involves gentle skincare practices. For some types, such as milia and keratosis pilaris, regular, gentle exfoliation helps remove keratin accumulation. This can be achieved with mild exfoliating scrubs or products containing alpha hydroxy acids (AHAs) like glycolic acid or beta hydroxy acids (BHAs) like salicylic acid. Consistent moisturizing is also beneficial, as it helps soften the keratin buildup and prevents dryness, which can worsen conditions like keratosis pilaris.
Prevention strategies vary depending on the specific type of deposit. For actinic keratoses, minimizing sun exposure and using broad-spectrum sunscreen with an SPF of at least 30 daily are steps. Proper footwear and protective padding help prevent calluses and corns by reducing friction and pressure on the skin. Maintaining a consistent skincare routine with gentle cleansers and avoiding harsh products also helps prevent clogged pores and general keratin buildup.
Consult a dermatologist if you notice any new skin growths, or if existing deposits change in size, shape, color, or texture, or become painful, itchy, or bleed. A professional evaluation ensures accurate diagnosis and appropriate treatment, ruling out more serious conditions like skin cancer.