Soft Tissue Infections Flashcards
How does impetigo present? What are the infecting pathogens?
Superficial skin infection
Multiple vesicular lesions on erythematous base
Golden crust is highly suggestive of this diagnosis
Most commonly due to SA
Less commonly strep pyogenes
Who most commonly present with impetigo? What are some predisposing factors?
Children age 2-5 Predisposing factors - skin abrasions - minor trauma - burns - poor hygiene - insect bites - chickenpox - eczema - atopic dermatitis
How is impetigo treated?
Small areas can be treated with topical antibiotics
Large areas need topical treatment and oral antibiotics e.g. flucloxacillin
What is erysipelas, how does it present, what is the usual organism?
Infection of upper dermis - 70-80% involves lower limbs
Painful, red area (no central clearing)
Associated fever
Regional lymphadenopathy and lymphangitis
Distinct elevated borders
Tends to occur in areas of pre-existing lymphoedema, venous stasis, obesity, paraparesis, diabetes mellitus
Most commonly due to strep pyogenes
What is cellulitis, how does it present, what are the likely organisms? Predisposing factors?
Diffuse skin infection involving deep dermis and subcutaneous fat
Presents as a spreading erythematous area with no distinct borderes
Fever is common
Regional lymphadenopathy and lymphangitis
Most likely due to strep pyogenes, SA
Predisposing factors - diabetes mellitus, tinea pedis, lymphoedema
How are erysipelas and cellulitis treated?
Combination of anti-staphylococcal and anti-streptococcal antibiotics
IV and admission if extension
What are some hair-associated infections?
Folliculitis
Furunculosis
Carbuncles
How does folliculitis present? What is the most common organism?
Circumscribed, pustular infection of hair follicle
Up to 5mm in diameter
Present as small red papules
Central area of purulence
Typically found on head, back, buttocks and extremities
Usually SA
How does furunculosis present? What is the most common organism and the risk factors?
‘Boils’
Single hair follicle inflammation extending into dermis and subcutaneous tissue
Usually affects moist/hairy/friction prone areas
Usually SA
Risk factors - diabetes, obesity, CKD, corticosteroid use
What is a carbuncle? How does it present?
Occurs when infection extends to involve multiple furuncles
Often located on back of neck, posterior trunk or thigh
Multiseptated abscesses
Constitutional signs common
How are hair-associated infections treated?
Folliculitis - none or topical antibiotics
Furunculosis - none or topical antibiotics, oral if required
Carbuncles - often need admission, surgery and IV antibiotics
What are the different types of necrotising fasciitis? What are the typical organisms? What are some predisposing factors?
Type I - mixed aerobic/anaerobic
- streptococci, staphylococci, enterococci, gram negs, clostridium
Type II - monomicrobial
- normally strep pyogenes
Predisposing
- Diabetes mellitus
- surgery
- trauma
- peripheral vascular disease
- skin popping
How does necrotising fasciitis present? What symptom/sign is highly suggestive of this disease?
Rapid onset
Sequential development of erythema, extensive oedema, and severe unremitting pain
Haemorrhagic bullae, skin necrosis, and crepitus may develop
Systemic features
- fever
- hypotension/tachycardia
- delirium
- multi-organ failure
Anaesthesia at site of infection is highly suggestive
How is necrotising fasciitis treated?
Surgical review mandatory Broad spectrum antibiotics - flucloxacillin - gentamicin - clindamycin
Don’t let imaging delay treatment
What is pyomyositis, how does it present, what causes it, how is it treated?
Purulent infection deep within striated muscles Multiple sites can be involved Constitutional symptoms common Commonest cause SA Surgery may be needed
