Desquamated Corneocytes: Composition and Origin

Nature and Formation of Skin Sheddings

Human skin is constantly regenerating, with cells produced in the deeper layers gradually migrating to the surface. As these cells reach the outermost layer of the epidermis, the stratum corneum, they undergo a process of terminal differentiation, becoming flattened, non-nucleated corneocytes. These are eventually shed from the skin surface in a process known as desquamation.

Composition and Characteristics

These shed skin particles are primarily composed of keratin, a fibrous structural protein that provides strength and resilience. Lipids, including ceramides, cholesterol, and fatty acids, are also present, contributing to the skin's barrier function and moisture retention. These corneocytes measure typically between 20-40 μm in diameter.

Origin and Rate of Production

The process of skin cell turnover begins in the stratum basale, the deepest layer of the epidermis. It takes approximately 4 to 6 weeks for cells to migrate from the stratum basale to the stratum corneum. The rate of shedding varies between individuals and body regions, influenced by factors such as age, genetics, environmental conditions, and skin health.

Factors Influencing Shedding

• Age: Skin cell turnover slows with age.
• Hydration: Dry skin tends to shed more visibly.
• Skin Conditions: Eczema, psoriasis, and other skin disorders can increase the rate of shedding.
• Environmental Factors: Dry air, sun exposure, and harsh chemicals can influence the desquamation process.

Relevance to Allergies and Hygiene

These microscopic particles act as carriers for allergens, particularly those associated with house dust mites. The mites feed on the organic matter within these shed skin cells, making them a significant component of household dust and a major trigger for allergic reactions in susceptible individuals. Regular cleaning and proper ventilation can help reduce the concentration of these particles in indoor environments.