Lecture 15 - Chapter 18 - Diseases of the Skin and Eye Flashcards
skin swelling over the pore leading out of a hair follicle
comedo
A mass of sebum and dead cells trapping pores associated with hair follicles
acne
a comedo with a closed pore
“Whitehead”:
a comedo with a pore open to the surface of the skin
“Blackhead”:
based on signs and symptomss
anatomical diagnosis
identifying the causative agent
etiological diagnosis
a lesion that has erupted on the surface
pustule or papule
pustules that come to involve deeper layers of skin
cysts
widespread cysts
cystic acne
A superficial bacterial infection that causes the skin to flake or peel off.
impetigo
what disease is caused by either staphylococcus aureus or streptococcus pyogenes or a mix of these two
impetigo
primary victims of impetigo
children
- Causes many types of infections
- Gram-+ coccus that forms grape-like clusters
- Metabolically versatile
- Produces exfoliative toxins A & B, coagulase, hyaluronidase, staphylokinase, DNase, and lipases
- With stand high salt in medium
- Can ferment mannitol
- Mannitol salt agar is differntial and selective for S. aureus growth
impetigo - staphylococcus aureus
impetigo test for S. aureus
coagulase test
positive coagulase test
plasma clots or becomes lumpy
- causes strep throat, scarlet fever, puerperal fever, necrotizing fasciitis, bloodstream infections, and rheumatic fever
- Gram-positive coccus, beta-hemolytic
- Adhesive elements: LTA, M protein, hyaluronic acid capsule
- Produces hyaluronidase
impetigo - streptococcus pyogenes
Diagnosed by visual inspection, but symptoms alone won’t distinguish S. aureus and S. pyogenes
impetigo
antibiotics used to treat both types of impetigo
- topical mupirocin (Bactroban)
- protein synthesis inhibitor
Caused by a fast-spreading infection in the dermis and subcutaneous tissues.
cellulitis
- Usually follows the introduction of bacteria or fungi into the dermis through trauma or no obvious break in the skin
- lower leg
- People with immunocompromise or who have cardiac insufficiency are most at risk
- Pain tenderness, swelling and warmth.
- Fever and swelling of the lymph nodes in the area may be observed along with red lines leading away from the affected area
cellulitis
Dermolytic condition caused by S. aureus.
staphylococcal scalded skin syndrome (SSSS)
- A systemic form of impetigo
- Phage-encoded exfoliative toxins are responsible for symptoms
- Develops predominately in newborns and infants, can spread when sharing a nursery with a newborn who is colonized with S. aureus.
SSSS
- Caused by exfoliative toxins A and B
- Have the appearance of wrinkled tissue paper
- Lead to widespread desquamation of the skin
- Patients are left vulnerable to secondary bacterial infections
bullous lesions
- caused by a reaction to antibiotics, barbiturate or other drugs
- high mortality rate
TEN - toxic epidermal necrolysis
split between the dermis and epidermis
TEN
split is within the epidermis
SSSS
Clostridium perfringens
- Gram positive
- Endospore forming
- Anaerobic
gas gangrene
- Endospores are found in soil, human skin, human intestine and vagina
- Anaerobic conditions are required to manufacture and release the toxins that cause disease
gas gangrene
Exotoxins produced by C. perfringens:
- Alpha toxin: causes red blood cell rupture, edema, tissue damage
- Collagenase
- Hyaluronidase
- DNase
gas gangrene
treatment of gas gangrene
Immediate & rigorous cleaning Surgery to remove infected and dead tissue Hyperbaric oxygen therapy Amputation Clindamycin + penicillin
Two diseases that present as generalized rashes all over the body in which individual lesions contain fluid.
“Pox”
Chickenpox
Smallpox
vesicular or pustular rash diseases
- mild disease.
- resolve in 2 – 3 weeks
- Some experience secondary infections
- 20% mortality rate in immunocompromised people
- 0.1% of cases are followed by encephalopathy
- Vaccine available for infants 12 – 15 months and children 4 – 6 years
chickenpox