Skin and Soft Tissue Infections Flashcards
What things should be considered with skin and soft tissue infections?
- Site
- Organism
- Host
- Environment
What should be considered about the site of infection?
-Possible complications with specific sites (ex; abdo, face)
What should be considered about the organism causing infection?
Gram negative or gam positive
What should be considered about the infected host?
- Diabetes leading to neuropathy and vasculopathy
- Immunosuppression
- Renal failure
- Milroy’s disease (lymphatic system has not developed in specific part of the body, usually a limb)
- Predisposing skin conditions (ex; atopic dermatitis)
What should be considered about the environment with infection?
- Drug-resistant strains (MRSA)
- Drug interactions
- Drug allergies
What is impetigo?
A highly infection superficial skin infection
What is the presentation of impetigo?
- Multiple vesicular lesions on an erythematous base
- Golden crust is highly suggestive of this diagnosis
What organisms cause impetigo?
- Most commonly due to Staph aureus
- Less commonly Strep pyogenes
Where does impetigo usually affect?
Usually occurs on exposed parts of the body including face, extremities and scalp
Who usually gets impetigo?
Children aged 2-5
What are the predisposing factors for impetigo?
- Skin abrasions
- Minor trauma
- Burns
- Poor hygiene
- Insect bites
- Chickenpox
- Eczema
- Atopic dermatitis
What is the treatment for impetigo?
- Small areas can be treated with topical antibiotics alone
- Large areas need topical treatment and oral antibiotics (ex flucloxacillin)
What is erysipelas?
Infection of the upper dermis with a high recurrence rate (30% withi 3 years)
How does erysipelas present?
- Painful, red area (no central clearing)
- Associated fever
- Regional lymphadenopathy and lymphangitis
- Typically has distinct elevated borders
What organisms is commonly responsible for erysipelas?
Strep. pyogenes
Where does erysipelas usually affect?
- 70-80% of cases involves the lower limbs
- 5-20% affect the face
- Tends to occur in areas of pre-existing lymphoedema, venous stasis, obesity, paraparesis, diabetes mellitus
What is cellulitis?
Diffuse skin infection involving deep dermis and subcutaneous fat
How does cellulitis present?
- Presents as a spreading erythematous area with no distinct borders
- Fever is common
- Regional lymphadenopathy and lymphangitis
What are the most likely organisms involved in cellulitis?
- Strep pyogenes
- Staph aureus
What are the predisposing factors for cellulitis?
- Diabetes mellitus
- Tinea pedis
- Lymphoedema
What is the treatment for erysipelas?
- A combination of anti-staphylococcal and anti-streptococcal antibiotics
- In extensive disease, admission for intravenous antibiotics and rest
What is the treatment for cellulitis?
- A combination of anti-staphylococcal and anti-streptococcal antibiotics
- In extensive disease, admission for intravenous antibiotics and rest
Give examples of hair associated infections.
- Folliculitis
- Furunculosis
- Carbuncles
What is folliculitis?
- A circumscribed, pustular infection of a hair follicle, up to 5mm in diameter
- Benign
How does folliculitis present?
- Present as small red papules
- Central area of purulence that may rupture and drain
- Absence of constitutional symptoms
Where does folliculitis typically occur?
Head, back, buttocks and extremities
What is the most common organism in folliculitis?
Staph aureus
What is furunculosis?
- Furuncles are commonly referred to as boils.
- Single hair follicle-associated inflammatory nodule which extends into the dermis and subcutaneous tissue
Where does furunculosis commonly affect?
Moist, hairy friction-prone areas of the body (face, axilla, neck and buttocks)
What can furuncles spontaneously do?
Drain purulent material
What is the most common organism in furunculosis?
Staph aureus
What are the risk factors for furunculosis?
- Obesity
- Diabetes mellitus
- Atopic dermatitis
- Chronic kidney disease
- Corticosteroid use
When does carbuncle usually occur?
When infection extends to involve multiple furuncles
Where do carbuncles usually occur?
Often on the back of the neck, posterior trunk or thigh
What do carbuncles present?
- Multiseptated abscesses
- May express purulent material from multiple sites
- Constitutional symptoms are common
What is the treatment for folliculitis?
No treatment or topical antibiotics
What is the treatment for furunculosis?
- No treatment or topical antibiotics
- Oral antibiotics may be necessary if no improvement
What is the treatment for carbuncles?
Often require admission to hospital, surgery and IV antibiotics
What is necrotising fasciitis?
An infectious disease emergency
Where can necrotising fasciitis affect?
Any site
What are the predisposing factors for necrotising fasciitis?
- Diabetes mellitus
- Surgery
- Trauma
- Peripheral vascular disease
- Skin popping