Skin Infections Overview

Skin Infections

• Carbuncle: Damage and inflammation of deep tissue from a spreading furuncle.
• Scalded Skin Syndrome: Staphylococcal toxin affects skin layers.
• Folliculitis: Infections of hair follicles.
• Sty: Folliculitis of an eyelash.
• Furuncle: Localized pus surrounded by inflamed tissue, an abscess.
• Bullous Impetigo: Localized staphylococcal toxin causing blisters and crusts.
• Toxic Shock Syndrome: Systemic illness from staphylococcal toxin, possibly causing shock.
• Streptococcal Infections: Gram-positive cocci in chains causing skin infections.
• Hemolysins: Enzymes that lyse red blood cells in streptococci.
• Group A Streptococci: Includes Streptococcus pyogenes, with virulence factors like strep throat, cellulitis, and impetigo.
• M Proteins: External to cell wall allowing adherence and immune system avoidance in streptococci.
• Hyaluronidase: Enzyme dissolving connective tissue in infections.
• Streptokinases: Enzymes dissolving blood clots, aiding bacterial spread in infections.
• Erysipelas: S. pyogenes infection of the dermal layer, causing local destruction.
• Cellulitis: Deep skin infection often due to breaks, treated with antibiotics.
• Necrotizing Fasciitis: Rapidly progressing, “flesh-eating,” disease from S. pyogenes.
• Pseudomonas aeruginosa: Gram-negative rod causing infections; produces blue-green pus; opportunistic in burn patients.
• Pseudomonas Dermatitis: Self-limiting rash from exposure (e.g., swimming pools).
• Otitis Externa: Infection of the outer ear (swimmer's ear).
• Buruli Ulcer: Caused by Mycobacterium ulcerans; leads to deep ulcers.
• Acne: Blocked hair follicles due to sebum and bacteria.
• Warts: Small growths caused by papillomavirus (transmitted by contact).
• Smallpox: Caused by orthopoxvirus; eradicated.
• Chickenpox: Caused by varicella-zoster virus; leads to vesicular rash.
• Shingles: Reactivation of varicella-zoster virus along nerves.
• Herpes Simplex: Caused by HSV-1 and HSV-2; remains latent.
• Ringworm: Circular rash caused by fungal infection.
• Athlete's Foot: Fungal infection causing itchy rash on feet.
• Candidiasis: Overgrowth of Candida albicans in skin and mucous membranes.
• Scabies: Caused by Sarcoptes scabiei mites, causing inflammatory skin lesions.
• Pediculosis (Lice): Treatment with topical insecticides.
• Staphylococcus aureus: Carried in nasal passages of 20% of population; produces damaging toxins and causes sepsis.
• MRSA: Methicillin-resistant S. aureus; antibiotic resistant.
• Conjunctivitis: Inflammation of the conjunctiva, often caused by bacteria and viruses.
• Ophthalmia Neonatorum: Caused by Neisseria gonorrhoeae; can cause blindness in newborns.
• Inclusion Conjunctivitis: Caused by Chlamydia trachomatis, transmitted during birth or through swimming pools.
• Propionibacterium acnes: Anaerobic bacteria contributing to acne inflammation.
• Cutaneous Mycoses: Fungal infections of the skin.

Eye Infections

• Conjunctivitis: Inflammation of the conjunctiva.
• Ophthalmia Neonatorum: Caused by Neisseria gonorrhoeae, potentially causing blindness in newborns.
• Inclusion Conjunctivitis: Caused by Chlamydia trachomatis, transmitted during birth or through swimming pools.
• Trachoma: Chlamydia trachomatis, leading to scarring and blindness.
• Contaminated contact lenses may lead to keratitis.

Systemic Infections

• Sepsis: The body's extreme reaction to an infection.
• Toxic Shock Syndrome: Systemic illness from staphylococcal toxin.

Nervous System Infections

• Meningitis: Inflammation of the meninges.
• Bacterial Meningitis: Initial symptoms include fever, headache, and stiff neck; can lead to convulsions and coma.
• Pneumococcal Meningitis: Caused by Streptococcus pneumoniae, most common in children aged 1–4 years.
• Tetanus: Caused by Clostridium tetani, leading to muscle spasms and possible death.
• Botulism: Caused by Clostridium botulinum, leading to flaccid paralysis from exotoxin ingestion.
• Leprosy: Also called Hansen's disease, caused by Mycobacterium leprae; affects peripheral nerves and skin.
• Poliomyelitis: Caused by poliovirus, potential paralysis in some cases following initial symptoms.
• Rabies: Caused by rabies virus; typically animal-borne, leading to muscle spasms and hydrophobia.
• Encephalitis: Inflammation of the brain.
• Meningoencephalitis: Inflammation of both brain and meninges.

Other Infections

• Listeriosis: Caused by Listeria monocytogenes; usually foodborne and asymptomatic but can cause meningitis.
• Meningococcal Meningitis: Caused by Neisseria meningitidis, with a mortality rate of 9–12% with antibiotic therapy.
• T cell receptors: On T cell surface triggering cytokine release, not antibodies.

General Information

• Papules: Raised skin lesions.
• Showering with contact lenses: Risk of bacteria and parasites.