Chapter 21: Skin and Eye Infections - Vocabulary Flashcards

Vocabulary-style flashcards covering key skin and eye infection topics from Chapter 21 notes.

Staphylococcus aureus

Gram-positive cocci in clusters; highly pathogenic due to exotoxins and penicillinase; MRSA is the methicillin-resistant strain.

MRSA (methicillin-resistant Staphylococcus aureus)

Staph aureus strain resistant to methicillin; trend of increasing MRSA in ICU to outpatient populations; largely a nosocomial concern.

Boils (furuncles)

Localized Staphylococcus aureus infection; rupture creates risk of secondary bacterial infections entering through the portal of entry.

Impetigo

Superficial skin infection; can be caused by Staph aureus or Streptococcus pyogenes; causes blisters; common in children; contagious.

Scalded skin syndrome

Systemic infection caused by Staphylococcus aureus exotoxin; widespread red spots and peeling skin resembling scalding.

Streptococcus (Strep)

Gram-positive cocci; hemolytic enzymes observed as beta/alpha/gamma hemolysis on blood agar; degree of hemolysis correlates with pathogenicity.

Streptococcus pyogenes

Causative agent of strep throat; carriers ~5–15%; many sore throats are viral; bacterial strep requires testing and antibiotics.

Necrotizing fasciitis

“Flesh-eating” infection caused by Streptococcus; rapid tissue destruction; can be fatal within 12–24 hours; risk factors include immunocompromise and recent varicella infection.

Pseudomonas aeruginosa

Gram-negative bacillus; opportunistic, nosocomial; thrives in warm environments; resistant; grape-like odor; blue-green pus; often affects immunocompromised.

Pseudomonas virulence factors

Capsule with a glycocalyx; both endo- and exotoxins; contributes to environmental resilience and pathogenicity.

Hot tub folliculitis

Pseudomonas infection from contaminated hot tubs; mild rash after exposure; more likely with higher organism concentration.

Bacteremia (Pseudomonas)

Systemic spread of bacteria; Pseudomonas can cause bacteremia in immunocompromised individuals.

Human papillomavirus (HPV)

Virus that causes warts; infects the top layer of skin; highly contagious through direct/indirect contact; not restricted to genitalia.

Warts (HPV-associated)**

Raised skin lesions caused by HPV infection; transmission via contact; can spontaneously regress; duct tape therapy mentioned as a treatment option.

Varicella-zoster virus (VZV)

Herpesvirus causing chickenpox; remains latent for life and can reactivate as shingles; vaccine introduced in 1995.

Chickenpox (varicella)

Varicella infection transmitted mainly by respiratory route; latent in nerves; can cause encephalitis; lifelong dormancy.

Shingles (herpes zoster)

Reactivation of latent varicella-zoster virus; painful dermatomal rash; more common after age ~50; possible lingering postherpetic neuralgia.

Herpes simplex virus (HSV-1/HSV-2)

Enveloped virus with latency; HSV-1 typically oral, HSV-2 typically genital but not exclusive; can cause conjunctivitis and spread without symptoms.

Herpes conjunctivitis

Ocular infection caused by HSV; potentially serious as it can spread along the optic nerve to the CNS.

Conjunctivitis (pink eye)

Inflammation of the conjunctiva; can be bacterial, viral, or due to allergens/irritants; precaution advised; HSV conjunctivitis is particularly severe.

Ringworm (dermatophytes)

Fungal infection of skin (dermatophytes); highly contagious; circular, itchy lesions with raised edges; nails/hair involvement may require oral antifungals.

Stye

Bacterial infection of the eyelid usually by Staphylococcus aureus; swelling of eyelid; multiple styes may require antibiotics.

River blindness (onchocerciasis)

Helminthic eye infection caused by Onchocerca volvulus; transmitted by black fly; long incubation; heavy worm burden can cause blindness; treated with ivermectin; most cases in Africa.

Loa loa (eye worm)

Filariasis caused by Loa loa; vector is the deer fly; larvae migrate under skin and can be seen moving across the eye; diurnal migration patterns influence symptoms and treatment; treated with antiparasitics like ivermectin.

Ivermectin

Antiparasitic drug used to treat river blindness and loiasis; highly effective but toxic due to targeting eukaryotic organisms; immune reactions can occur.