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Skin Diseases



Trillions of microbes live on the skin, and while many of them thrive without causing disease, others are capable of causing painful and sometimes life-threatening infections. The skin possesses a range of natural defenses to pathogens, including physical and chemical barriers. Skin infections arise when microbes are able to penetrate the body's defenses, and they typically occur as rashes and other forms of inflammation. MRSA (methicillin-resistant Staphylococcus aureus) is a common and sometimes deadly bacterial skin pathogen that is resistant to many antibiotic treatments.

At A Glance

  • The skin is made up of three layers—epidermis, dermis, and hypodermis—and contains anatomical features including hair shafts, sweat pores, nerves, and capillaries.
  • Keratin, sebaceous glands, antimicrobial peptides, sebum, and lysozymes are all components of the skin's natural defenses.
  • The skin is colonized by a diverse community of microorganisms, including common strains of Staphylococcus.
  • Bacterial skin infections are often opportunistic, caused by native skin species, and mild, though there are serious bacterial skin diseases requiring rapid and aggressive treatment.
  • Staphylococcus aureus and Streptococcus pyogenes cause similar skin infections and should be differentiated before treatment.
  • MRSA (methicillin-resistant Staphylococcus aureus) is found naturally in 2 out of every 100 people in the United States and is responsible for many cases of life-threatening hospital-acquired infections.
  • Viral infections of the skin are widespread, highly contagious, and often recurring, though the most life-threatening are preventable with vaccinations.
  • Fungal skin infections are classified based on the location of the infection (scalp, body, beard, or foot). They are widespread and readily treatable with topical ointments.
  • Lice and mites are spread by direct or indirect contact, cause itchy skin infections, and are treated with topical medications.