Skin and Sot Tissue Infections Flashcards

(41 cards)

1
Q

Discuss the skin as a defensive barrier

A
• Epidermis – hard horny layer of dead cells
• Surface is dry
• Constant sloughing
• Acidic pH
• Sweat secretion
• Rich blood and lymphatic supply
• Produces antimicrobial substances e.g.
– fatty acids 
– sebum
– defensins
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2
Q

What is an abscess?

A

collection of pus; pustule

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3
Q

What is a (cutaneous) vesicle?

A

blister; bullae (plural); fluid filled sac

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4
Q

What is pyoderma?

A

pus-forming skin infection; cutaneous abscess

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5
Q

What is impetigo?

A

vesicles developing into rupturing pustules then forming dried crusts

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6
Q

What is ecthyma?

A

rupturing vesicles leading to erythematous lesions and dried crusts

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7
Q

What is folliculitis?

A

inflammation at hair follicle

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8
Q

What is a furuncle?

A

boil; deep folliculitis

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9
Q

What is a carbuncle?

A

collection of boils

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10
Q

What is erysipelas?

A

erythema and inflammation of superficial dermis

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11
Q

What is cellulitis?

A

erythematous inflammation affecting deeper dermis and subcutaneous fat

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12
Q

What is ACNE?

A

infection of sebaceous follicles

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13
Q

What is necrotising fasciitis?

A

cellulitis with necrosis affecting skin, deeper fascia and sometimes muscle

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14
Q

What is dehiscence?

A

wound rupture along surgical suture

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15
Q

What are some normal skin microbiota?

A
• Coagulase-negative Staphylococci 
– Staphylococcus epidermidis
– Staphylococcus aureus
• Streptococcus pyogenes 
• Propionibacterium acnes 
• Corynebacterium sp.
• Candida sp.
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16
Q

What are the routes of infection in the skin?

A
• Skin
– Pores
– Hair follicles
• Wounds
– Scratches
– Cuts
– Burns
• Bites
– Insects
– Animals
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17
Q

List 4 skin infections in order of superficiality

A

Impetigo
Erysipelas
Cellulitis
Necrotising fasciitis

18
Q

When taking a history about skin infection what should you ask abt?

A

• The onset, evolution, duration and location of lesions.
• Contacts with a similar rash.
• Past medical history noting skin conditions such
as eczema or immunosuppression.
• Skin trauma or abrasions or insect bites.
• Previous treatment including antimicrobial therapy.
• Systemic features such as fever

19
Q

Discuss management of skin infections in primary care

A
  • Class I cellulitis – draw a line around the lesion, prescribe high-dose oral antibiotics according to local guidelines
  • Pain relief and elevation
  • Deal with concomitant skin lesions

• Provide patient information on cellulitis. For example:
– Cellulitis or erysipelas published by the British Association of
Dermatologists (BAD, www.bad.org.uk).
– About cellulitis published by the Lymphoedema Support
Network (www.lymphoedema.org).
– Cellulitis published by NHS (www.nhs.uk).

– Refer patients with recurrent cellulitis
– Review in 48 hours

20
Q

Discuss general management of skin infection

A

• Referral rarely needed unless - part of an outbreak
- diagnostic uncertainty
- resistant to maximal treatment
- complications e.g., acute glomerulonephritis
• Advise hygiene measures help to aid healing and stop infection spreading:
– Wash affected areas with soap and water.
– Wash their hands regularly, in particular after touching a patch
of impetigo.
– Avoids scratching affected areas.
– Avoids sharing towels etc.,

21
Q

Are blood cultures necessary in skin infections?

A

Not always necessary but will take 24-48 to return so empiric therapy is usually required.

22
Q

What are some comorbidities of skin infections

A

Diabetes mellitus

Cathater related infection

23
Q

Name some fungal infections in the skin

A
• Dermatophytes 
– Tinea spp.
– e.g. Tinea pedis
– e.g. Tinea corporis 
– e.g. Tinea cruris
• Yeasts
– Candida albicans 
– Malassezia furfur
24
Q

Name a parasite that can cause an infection?

25
How may ringworm present?
As ringworm of the skin and ringworm of the groin
26
What is a famous skin infection of the foot?
Athlete's foot
27
Name some viral infections of the skin
* Human papilloma viruses (HPV) - Warts * Herpes simplex virus 1 (HSV1) - Cold sores * Herpes simplex virus 2 (HSV2) - Genital warts * Varicella zoster virus (VZV) - Chicken pox, shingles * Coxsackie A virus – Hand, foot and mouth disease
28
What is the impact of sarcoptes scabei (mite)
``` – Causes scabies – Mite burrows into skin – Female lays eggs – Infection is asymptomatic – Hypersensitivity may occur – May lead to superinfection ```
29
Discuss the epidemiology of animal bites
``` – 250 000 cases A+E UK / yr • 3% visits – Dogs 80-90% > cat > human – Children > adults – Site • Children – facial / cervical • Adults – extremities ```
30
What should be considered in an animal bite?
What structures have been affected? What part of the body is affected? What (if any) infection is going to result? Any expected complications? Management?
31
Discuss cat bites
Small deep wound (2-5 cm) Usually periphery (small mouths) (hand, foot) Pasteurella spp. Cellulitis Assess!
32
Discuss pasteurella multocida
• Animal commensal + pathogen – Fowl cholera, swine atrophic rhinitis, RTI rabbits, bovine septicaemia I V • Zoonosis – Bites, septic arthritis, septicaemia, meningitis, osteomyelitis
33
Discuss dog bites
Large wound: tearing, crushing Usually periphery but can occur anywhere Secondary infections: large area damaged, high chance of contamination (dog, environment) Crush damage comes with its own complications Surgery – extensive superficial damage and crushing
34
Discuss human bites
Wide shallow wound Anywhere... Highly polymicrobial Deep infection is common, viral infection Drastically different- Assess
35
What is the animal bite 'mantra'?
“The Solution to Pollution is Dilution”
36
Discuss the microbiology of bites?
``` • Polymicrobial! • Human – average 5 microorganisms will infect – 60% anaerobes – Eikenella corrodens 1⁄4 hand bites – Group A Strep (S. pyogenes) • Viral aetiology (risk assess) – rabies (remember bats!) – Simian herpes virus, – Hep B, HIV, Hep C ```
37
What are the important points of management of bites?
``` • Full history – immunodeficiency, country of exposure • Radiology – clenched fist, scalp bites (children) • Wound exploration – irrigate / debride = SOURCE CONTROL – delayed closure • Antibiotic therapy – prophylaxis – treatment ```
38
What length antibiotic course should be given for cellulitis?
7- 10 days
39
What length antibiotic course should be given for tenosynovitis?
21 days
40
What length antibiotic course should be given for septic arthritis?
28 days
41
What length antibiotic course should be given for osteomyelitis?
42 days