Skin and Eyes Diseases

Staphylococcus epidermidis

90% of normal skin microbiota ; healthcare-associated pathogen (biofilm on catheters)

Staphylococcus aureus

• May produce damaging toxins and cause sepsis.

• Secretes proteins and toxins that kill phagocytes.

MRSA strains of Staphylococcus aureus

Antibiotic resistant

Folliculitis

Infection of hair follicles ; Staphylococcal

Furuncle / Boil

Type of abscess ; Staphylococcal

Carbuncle

Damage and inflammation of deep tissue from spreading furuncle ; Staphylococcal

Impetigo

Crusting (nonbullous) sores spread from one body part to another ; can be caused by Streptococcus pyogenes or Staphylococcal

Scalded Skin Syndrome

Bullous impetigo ; exfoliative toxin A and B ; Staphylococcal

Exfoliative Toxin A of Scalded Skin Syndrome

Bullous impetigo remains localized in an area.

Exfoliative Toxin B of Scalded Skin Syndrome

Bulbous impetigo spreads to distant sites.

Toxic Shock Syndrome (TSS)

Fever, vomiting, shock, and organ failure caused by toxic shock syndrome toxin 1 (TSST-1) in blood ; Staphylococcal

What is TSS associated with?

Tampon use and nasal surgery

Streptococcal Skin Infections

Gram positive chain cocci; produce hemolysins

Staphylococcal Skin Infections

Spherical gram-positive bacteria ; forms clusters

How is Streptococci differentiated?

Into groups A-T based on antigenic cell wall carbohydrates

Group A Streptococci (GAS)

Streptococcus pyogens ; produce virulence factors

Virulence factors of GAS

• Streptolysins

• M Proteins

• Hyalauronidase

• Streptokinases

Streptolysins

Lyse RBCs

M Proteins

Blocks complement activation, enables evasion of phagocytes, kill neutrophils, and allow bacteria to adhere to mucous membrane ; external to cell wall.

Hyaluronidase

Dissolves connect tissue

Streptokinases

Dissolve blood clots that isolate bacteria.

Erysipelas

S. pyogenes infect dermal layer of skin causing local tissue destruction and sepsis

Necrotizing Fasciitis

“Flesh eating” disease ; pyrogenic toxin produced by S. pyogenes acts as superantigen

Streptococcal Toxic Shock Syndrome

Fever, vomiting, shock, and organ failure; more deadly than regular TSS

Pemphigus neonatorum

impetigo of the newborn

Human herpesvirus 1 (HSV-1) / Herpes Simplex

• Spread primarily by oral or respiratory routes

• Usually develop as cold sores or fever blisters

• 90% of the U.S. population is infected

What is HSV-1 triggered by?

Sun, stress, or hormonal changes

What is used to treat HSV-1

Acyclovir

Varicella / Chickenpox

• Herpesvirus varicella-zoster (human herpesvirus 3)

• Transmitted via the respiratory route

• Causes pus-filled vesicles after a 10–14 day
  incubation

Reye’s syndrome

Severe complications of chickenpox; vomiting and brain dysfunction ; aspirin increase risk

Shingles / Herpes Zoster

Reactivation of the latent varicella-zoster virus that moves from dorsal root ganglia along peripheral nerves to the skin ; due to high stress of lowered immunity

Postherpetic neuralgia

Painful stinging and burning sensation for months to years following shingles

Treatment for Shingles

Acyclovir, valacyclovir, famciclovir may lessen symptoms

Measles

• Cold-like symptoms, macular rash, Koplik’s spots

• Infected individual sheds virus for several days before
  symptoms appear

• Transmitted by the respiratory route

Koplik’s spots

Red spots on the oral mucosa opposite the molars

Subacute sclerosing panencephalitis

A rare, progressive, and fatal neurological disorder caused by a persistent, mutated measles virus infection ; caused by reactivation of old measles virus

MMR Vaccine

Measles, mumps, and rubella vaccine

TORCH Screen

Panel of tests that screens for antibodies to infections in pregnant women or in newborn

TORCH Screen acronym

• T - toxoplasmosis

• O - other (syphilis, chickenpox, HIV, measles, mumps, hep B)

• R - rubella

• C - cytomegalovirus

• H - herpes simplex

Conjunctivitis / Pink Eye

Inflammation of the conjunctiva ; commonly caused by Haemophilus influenzae

Ophthalmia Neonatorum

• Large amount of pus forms; ulceration of corneas results

• Caused by Neisseria gonorrhoeae

• Transmitted to a newborn’s eyes during passage through
  the birth canal

Trachoma

• Infection causes permanent scarring; scars abrade the cornea, leading to blindness

• Caused by some serotypes of Chlamydia trachomatis

• Transmitted via hand contact or flies

Leading cause of blindness worldwide

Trachoma