Infections of the Skin Flashcards
(38 cards)
How does skin act as a defensive barrier?
1- Layer of dry dead cells 2- Surface always sloughing/shedding 3- Low pH 4- Sweat secretion 5- Rich blood and lymphatic supply 6- Produces antimicrobial substances
What antimicrobial substances does the skin produce?
1- Fatty acids
2- Sebum
3- Defensins
What are the six normal skin microbiota?
1- Coagulase-negative staphylococcus epidermis
2- Coagulase-negative staphylococcus aureus
3- Streptococcus pyogens
4- Propionibacterium acnes
5- Corynebacterium sp.
6- Candida sp.
Where does ringworm occur?
Keratinised epithelium
Where does impetigo occur?
Epidermis
Where does folliculitis occur?
Hair follicles
Where does cellulitis occur?
Subcutaneous fat
Where does necrotising fascitis occur?
Fascia
Where does gas gangrene occur?
Muscle
What are the three routs of skin infection?
Skin- pores, hair follicles
Wounds- scratches, burns, cuts
BItes- insects, animals
What are four examples of bacterial infections of the skin?
1- Staphylococcus aureus
2- Streptococcus pyogens
3- Pseudomonas aeruginosa
4- Mycobacterium tuberculosis
What are the features of Streptococcus pyogens?
1- Cocci 2- Grows in chains 3- Gram-positive (purple) 4- Group A Streptococcus (GAS) 5- Multiple virulence factors 6- Beta-haemolytic
What are the features of Staphylococcus aureus?
1- Cocci 2- Grows in clusters 3- Gram-positive (purple) 4- Causes huge range of illnesses 5- Has two antibiotic resistance strains, MRSA and VRSA 6- Multiple virulence factors 7- Direct infection of effect of toxin
What are the features of Pseudomonas aeruginosa?
1- Coccobacillus 2- Gram-negative (red/pink) 3- Monotrichous flagellum 4- Opportunistic 5- Colonises catheters and similar things 6- Produces exotoxin A
What produces exotoxin A?
Pseudomonas aeruginosa
What are the four different forms of skin legions?
1- Macule
2- Papule
3- Vesicle
4- Ulcer
What is a macule?
1- Skin legion
2- Flat, red, local inflammation
What is a papule?
1- Skin legion
2- Raised, red, more marked inflammation
What is a vesicle?
1- Skin lesion
2- Small blister
What is an ulcer?
1- Skin lesion
2- Disruption of epithelium
What is an abcess?
1- Collection of pus or a pustule
What is a cutaneous vesicle?
1- Blister
2- Bulla, plural = bullae
3- Fluid filled sac
What is a pyoderma?
1- Pus-forming skin infection
2- Cutaneous abscess
What is impetigo?
Vesicles developing into rupturing pustules then forming dried crusts
