How Skin Prevents Infection: 9 Protective Mechanisms

The skin is a multi-layered defense organ. Key protective mechanisms:

1. Physical Barrier: Stratum corneum—dead, keratinized cells block pathogen entry.
2. Acidic pH (4.5–5.5): Inhibits many bacteria and fungi.
3. Resident Microbiome: Commensals compete with pathogens for nutrients and space.
4. Desquamation: Continuous shedding removes attached microbes.
5. Keratinization: Tough, water-resistant keratin fortifies the surface.
6. Sebum: Oily film from sebaceous glands traps and inhibits microbes.
7. Sweat: Contains antimicrobial peptides (e.g., dermcidin); evaporation cools and limits bacterial growth.
8. Immune Cells: Langerhans cells, dermal dendritic cells detect and present antigens.
9. Wound Healing: Rapid clot formation, immune recruitment, and tissue repair seal breaches.

Compromised skin (burns, cuts, dermatitis) increases infection risk—proper care is vital.