Diseases of the Skin Flashcards
Chapter 21
1
Q
What is an important physical barrier to infections?
A
Intact Skin
2
Q
What are other important physical barriers to infections? (3)
A
- Epidermis
- Mucous Membranes
- Eyes
3
Q
(T/F) Eyes have normal flora
A
False
4
Q
What causes infections? (4)
A
- bacteria
- viruses
- fungi
- parasites
5
Q
What two bacteria cause the most common superficial skin infections?
A
- Staphylococcal
- Streptococcus
6
Q
Is normal flora Gram (+) or Gram (-) ?
A
Primarily Gram (+)
7
Q
Give examples of Normal Flora (5):
A
- Staphylococcus
- Micrococcus
- Diptheroids
- Propionibacterium acnes
- Corynebacterium xerosis
8
Q
Describe Diptheroids (2):
A
- Gram (+)
- Pleomorphic rods
9
Q
What does pleomorphic mean?
A
Can change shape and size
10
Q
What on the skin contains nutrients? (2)
A
- perspiration
- sebum
11
Q
What on the skin inhibits microbes/pathogens? (2)
A
- salt
- fatty acids (some)
12
Q
What does lysozyme do?
A
Hydrolyzes peptidoglycan
13
Q
Define Vesicles:
A
Small, fluid-filled lesions
14
Q
Define Bullae:
A
Vesicles larger than 1 cm in diameter
15
Q
Define Macules:
A
Flat, reddened lesions
16
Q
Define Papules:
A
Raised Lesions
17
Q
Define Pustules
A
Raised lesions with pus
18
Q
Define Exanthem:
A
Skin rash arising from a disease
19
Q
Define Enanthem:
A
Rash on mucous membranes arising from a disease
20
Q
Describe Staphylococcal Infections (2):
A
- Gram +
- coccus (grape-like clusters)
21
Q
What virulence factors do Staphylococcal Infections have? (5)
A
- Coagulase
- Leukocidin
- Exfoliative Exotoxins
- Enterotoxins
- Toxic Shock Syndrome Toxin
22
Q
What does Coagulase do?
A
Clots blood plasma (protects against phagocytosis)
23
Q
What does Coagulase protects pathogens from?
A
Phagocytosis
24
Q
What does Leukocidin do?
A
Destroys phagocytes
25
What does Exfoliative Exotoxins do?
Cause Scalded Skin Syndrome (SSS)
26
What do Enterotoxins cause?
Food Poisoning (Later)
27
Describe Staphylococcus aureus (2):
- (Most) Coagulase Positive
- (Most) Pathogenic
28
How does Staphylococcus aureus enter the body? (3)
- nasal passages
- hair follicles
- skin abrasions (enters blood)
29
What diseases does Staphylococcus aureus cause? (5)
- Folliculitis
- Boils
- Sty
- Carbuncles
- Impetigo
30
What is Folliculitis?
Pimples, pustules
31
What are other names for boils? (2)
- Furuncles
- Abscesses
32
What are Boils?
Deeper, pus-filled infection
33
What are Stys?
Infection at base of an eyelash
34
What are Carbuncles?
Deeper infection, progressively invasive
35
Describe Carbuncles (4):
- usually encapsulated
- no circulation
- many are MRSA (methicillin resistant)
- harder to treat
36
What is Impetigo?
Highly contagious, crusty lesions
37
Describe Toxic Shock Syndrome (3)
- life threatening
- occurs in menstruating women (highly absorbent tampons)
- strain that produces and exotoxin (TSST-1)
38
What are the Symptoms of Toxic Shock Syndrome? (6)
- fever
- sun burn rash
- vomiting
- decreases in blood pressure (leads to...)
- shock
- death
39
Describe Staphylococcus epidermidis (2):
- coagulase negative strain
- mainly normal flora
40
Describe Streptococcal Infections (3):
- gram (+)
- coccus (grows in chains)
- divided into 3 groups (hemolysins)
41
What are the three hemolysins? (3)
- Alpha
- Beta
- Gamma
42
Describe Alpha Hemolytic:
Partial RBC breakdown
43
Describe Beta Hemolytic:
Complete RBC breakdown
44
Describe Gamma Hemolytic:
No RBC breakdown
45
Which hemolysin is the most pathogenic?
Beta Hemolytic
46
What are Beta Hemolytic further divided into?
Groups A-T
47
Which Beta Hemolytic Group causes the most disease?
Group A Streptococci (GAS)
48
What is an example of a Group A Streptococci (GAS)?
Streptococci pyogenes
49
What differentiates S. pyogenes?
M Protein
50
What are the virulence factors of Streptococcal Infections? (8)
- Hemolysins
- M Protein
- Erythrogenic toxin
- DNAse
- Streptokinase
- Hyaluronidase
- Leukocidins
- Capsules
51
What known diseases are Streptococcal Infections? (3)
- Erysipelas
- Impetigo
- Necrotizing fasciitis
52
Describe Necrotizing Fasciitis (5)
- Group A Streptococci (Beta Hemolytic)
- Streptococcus pyogenes
- Highly invasive infection
- Strains produce enzymes
- Reach deeper tissues (damage/destroy muscles)
53
In simple terms, what is Necrotizing Fasciitis?
Flesh eating bacteria
54
What enzymes do strains of Necrotizing Fasciitis produce? (3)
- hyaluronidase
- protease
- streptokinase
55
How is Necrotizing Fasciitis treated? (2)
- Surgical removal of infected tissues
- IV antibiotic therapy
56
What are examples of Viral Skin Diseases? (6)
- German Measles (Rubella)
- Measles (Rubeola)
- Chickenpox & Shingles
- Smallpox
- Warts (HPV)
- Herpes Simplex
57
Describe Warts (3):
- Human papilloma virus (HPV)
- Most are benign skin tumors
- Found on fingers, larynx, genitals
58
Describe the Human Papilloma Virus (3):
- Double Stranded
- DNA
- Non-enveloped
59
How is HPV spread? (2)
Direct Contact
- Humans or Fomites
- Sexually Transmitted (Genital Warts)
60
How is HPV treated? (3)
- Freezing (liquid nitrogen)
- Burning (Acids)
- Laser Therapy
61
Describe Smallpox (4):
- Poxviridae
- Double stranded
- DNA
- Enveloped
62
What are the two forms of Poxviridae?
- Variola Major (20% die)
- Variola Minor (~1% die)
63
How is smallpox spread?
Respiratory route -> Blood -> Skin
64
How many incubation days for smallpox?
12 days
65
What cells does smallpox infect? (3)
- phagocytic cells
- blood cells
- skin (face then trunk)
66
What is a systemic infection?
One in the bloodstream
67
What is viremia?
Virus in the bloodstream
68
When was smallpox eradicated?
1980
69
How was smallpox eradicated? (2)
- vaccination (live attenuated vaccine)
- humans are only carriers (reservoir)
70
What virus causes chickenpox?
Varicella
71
What virus cases shingles?
Zoster
72
Describe Chickenpox & Shingles (4):
- Highly Contagious
- may remain in a latent stage
- causes small, irregular skin lesions
- Varicella-Zoster
73
Describe Varicella-Zoster Virus (3):
- Double Stranded
- DNA
- Enveloped
74
How are Chickenpox and Shingles spread?
Respiratory Route -> Blood -> Skin
75
How many incubation days for Chickenpox & Shingles?
14-16 days
76
Where are Chickenpox & Shingles latent in?
Dorsal root ganglion
77
What is shingles the result of?
Reactivation of Latent VZV
78
Can someone who's never had chickenpox get shingles?
No! You can only get shingles if you have had chickenpox beforehand
79
What reactivates Chickenpox/Shingles? (2)
- stress
- immune deficiency
80
What are treatments for Chickenpox/Shingles?
Acyclovir
81
What vaccines are available for Chickenpox/Shingles? (2)
- Varivax
- Shingrex
82
Describe the Varivax Vaccine (2):
- Attenuated Live
- Recommended for young children (12-24 months)
83
Describe the Shingrex Vaccine (2):
- subunit vaccine (parts of viral envelope)
- over 50 years
- prevents shingles
84
Describe Measles (Rubeola) (5):
- Highly Contagious
- Paramyxoviridae
- Humans are the only reservoir
- Macular Skin Rash (face -> trunk)
- Koplik's Spots
85
Describe Paramyxoviridae
- (-) RNA
- Enveloped
86
How are Measles (Rubeola) spread?
Respiratory Route
87
How many incubation days for Measles (Rubeola)?
10-12 days
88
What are the symptoms for measles? (3)
- Runny Nose
- Fever
- Sore Throat
89
What are Koplik's Spots?
Small, raised, red spots with white center on oral mucosa
90
Where are Koplik's Spots found?
On oral mucosa
91
What complications occur with Rubeola?
Ear infections - Severe Pneumonia
92
What form of measles is fatal?
Subacute Sclerosing Panencephalitis (SSPE)
93
How common is SSPE?
Very Rare
94
What vaccines are there for Rubeola?
MMR (measles mumps rubeola) vaccine
95
Describe the MMR Vaccine (3):
- 1963
- live attenuated vaccine
- given at 15-18 months of age
96
Describe Rubella (German Measles) (3):
- Togaviridae
- Mild
- Skin Rash
97
Describe Togaviridae (3):
- (+) RNA
- Enveloped
- Causes Exanthema
98
What is Exanthema?
Skin Rash
99
How is Rubella spread?
Respiratory Route -> Skin
100
How long is the incubation period for German Measles?
2-3 weeks
101
What does Rubella cause?
Small macular rash (not raised) with fever
102
What complications can occur with Rubella?
Encephalitis (may be fatal)
103
When can complications with Rubella occur?
First trimester of pregnancy (Congenital Rubella)
104
What is Congenital Rubella?
Maternal infection with Rubella Virus during pregnancy
105
What vaccine is there for German Measles?
MMR Vaccine
106
What does Congenital Rubella Syndrome cause? (2)
- Severe Fetal Damage
- Death
107
How can Congenital Rubella be prevented?
Through Vaccination
