Skin abscess
A skin abscess is a purulent, fluctuant collection within the dermis and subcutaneous fat, usually caused by Staphylococcus aureus including MRSA, whose primary treatment is incision and drainage, with antibiotics reserved as an adjunct by size and systemic signs.
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What this article covers
- Overview
Definition: a skin abscess is an erythematous, nodular, fluctuant, localized collection of pus within the dermis and subcutaneous fat, distinguishing it from Cellulitis, a nonpurulent, spreading infection with no drainable collection.
- Epidemiology
Common presentation: purulent skin infections including furuncles, carbuncles, and abscesses are a frequent cause of skin and soft tissue infection evaluation, particularly where community-associated MRSA is prevalent.
- Risk factors
Skin barrier disruption: trauma, shaving, injection drug use, or a pre-existing follicular or cystic lesion (for example a ruptured epidermal inclusion cyst) provides the nidus for a purulent collection.
- Pathophysiology
Follicular or cutaneous origin: infection typically begins in a hair follicle (folliculitis) and progresses to a walled-off collection of neutrophils and necrotic debris as Staphylococcus aureus proliferates locally.
- Clinical features
Fluctuant, tender, erythematous nodule: the hallmark finding; palpation reveals a soft, compressible center indicating an underlying purulent collection.
- Differential diagnosis
Cellulitis: spreading, poorly demarcated erythema without a discrete fluctuant or purulent component; abscess has a palpable, drainable collection.
- Diagnosis
Skin abscess is a clinical diagnosis, confirmed on inspection: the diagnosis is established by the finding of a fluctuant, tender, purulent collection on physical exam; two or more inflammatory signs…
- Management
First, perform incision and drainage: this is the primary treatment for abscesses, furuncles, and carbuncles regardless of size; make an adequate incision at the point of maximal fluctuance, break up…
- Complications
Progression to cellulitis or lymphangitis: untreated or inadequately drained abscess can spread to surrounding tissue.
- Prognosis
Excellent with adequate incision and drainage: most localized abscesses, furuncles, and even carbuncles resolve fully once source control is achieved.
- Prevention
Hygiene measures for recurrent purulent infection: daily chlorhexidine washes and regular handwashing reduce recurrent MRSA transmission.
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Related articles
- Cellulitis
Cellulitis is a nonpurulent, spreading infection of the deep dermis and subcutaneous fat, usually caused by beta-hemolytic streptococci, diagnosed clinically and treated with antibiotics alone since there is no collection to drain.
- Infectious folliculitis
Infectious folliculitis is a superficial inflammation or infection of the hair follicle, most often bacterial (Staphylococcus aureus or hot-tub-associated Pseudomonas aeruginosa) but also fungal, viral, or Demodex, diagnosed clinically and usually self-limited, with topical or oral antistaphylococcal therapy reserved for extensive or refractory disease.
- Impetigo
Impetigo is a superficial epidermal infection caused by Staphylococcus aureus or group A streptococcus, presenting as bullous or, more commonly, nonbullous honey-crusted erosions, diagnosed clinically, and treated with topical mupirocin for localized disease or oral antistaphylococcal antibiotics for widespread, bullous, or MRSA-associated infection.