Abscess, Skin/Soft Tissue, Emergency Medicine

Basics

Description

A localized collection of pus surrounded and walled off by inflamed tissue. Abscesses can occur on any part of the body
Furuncle:
- Arises from infected hair follicle
- Most common on back, axilla, and lower extremities
Carbuncle:
- Larger and more extensive than furuncle
Dog/cat bite:
- Usually polymicrobial
Breast:
- Puerperal:
  - Usually during lactation
  - Located in peripheral wedge
  - Usually staphylococci
- Duct ectasia:
  - Caused by ecstatic ducts
  - Periareolar location
  - Usually polymicrobial
Hidradenitis suppurativa:
- Chronic abscess of apocrine sweat glands
- Groin and scalp
- Staphylococcus aureus and staphylococcus viridans are common
- Escherichia coli and Proteus may be present in chronic disease
Pilonidal abscess:
- Epithelial disruption of gluteal fold over coccyx
- Staphylococcal species are most common
- May be polymicrobial
Bartholin abscess:
- Obstruction of Bartholin duct
Perirectal abscess:
- Originates in anal crypts and extends through ischiorectal space
- Inflammatory bowel disease and diabetes are predisposing factors
- Bacteroides fragilis and E. coli are most common
- Requires operative drainage
Muscle (pyomyositis):
- Typically in the tropics
- S. aureus is most common
IV drug abuse:
- Staphylococcal species are most common
- MRSA is common
- May be sterile
Paronychia:
- Infection around nail fold
- Usually S. aureus
Felon:
- Closed space abscess in distal pulp of finger
- Usually S. aureus

Etiology

Abscess formation typically occurs due to a break in the skin, obstruction of sebaceous or sweats glands, or inflammation of hair follicles. The collection may be classified as bacterial or sterile:
Bacterial: Most abscesses are bacterial with the microbiology reflective of the microflora of the involved body part:
- S. aureus is the most common causative organism
- Community-acquired MRSA (CA-MRSA) common
Sterile: More associated with IV drug abuse and injection of chemical irritants
Risk factors for abscess formation:
- Immunosuppression
- Soft tissue trauma
- Mammalian/human bites
- Tissue ischemia
- IV drug use
- Chrons disease (perirectal)

Diagnosis

Signs and Symptoms

Local:
- Erythema
- Tenderness
- Heat
- Swelling
- Fluctuance
- May have surrounding cellulitis
- Regional lymphadenopathy and lymphangitis may occur
Systemic:
- Often absent
- Patients with extensive soft tissue involvement, necrotizing fasciitis, or underlying bacteremia may present with signs of sepsis including:
  - Fever
  - Rigors
  - Hypotension
  - Altered mentation

History

Previous episodes: Raise concern for CA-MRSA
Immunosuppression
Medications:
- Chronic steroids, chemotherapy
IVDU
History of mammalian bite

Physical Exam

Location and extent of infection
Presence of:
- Associated cellulitis
- Subcutaneous air
- Deep structure involvement
Involvement of specialty area:
- Perirectal
- Hand
- Face/neck

Essential Workup

History and physical exam
Gram stain unnecessary for simple abscesses in healthy patients
Wound cultures:
- Not indicated in simple abscesses
- May help guide therapy if systemic treatment is planned
- May be useful in confirming CA-MRSA in patients with recurrent abscesses
- May guide specific therapy in a compromised host, abscesses of the central face or hand, and treatment failures

Diagnosis Tests & Interpretation

Lab

Routine laboratory tests are not typically indicated.
Glucose determination may be useful if:
- Underlying undiagnosed diabetes is a concern
- There is a concern for associated DKA
For febrile patients who appear septic, systemically ill, or have recent IVDU the following labs are indicated:
- Blood cultures
- Lactate
- Renal function
- CK if myositis suspected

Imaging

Bedside US can be helpful in distinguishing cellulitis from abscess
CT/MRI can be helpful in determining deep tissue involvement
Plain films may reveal gas in tissue planes

Differential Diagnosis

Cellulitis
Necrotizing fasciitis
Aneurysm (especially with IV drug abusers)
Cysts
Hematoma

Treatment

Pre-Hospital

Caution: Septic patients may require rapid transport with IV access and volume resuscitation.

Initial Stabilization/Therapy

Septic patient:

Immediate IV access
Oxygen
Crystalloid volume resuscitation
Blood cultures/lactate
Early antibiotic therapy-broad spectrum to include MRSA coverage.
Rapid source control (abscess drainage)
If patient remains hypotensive after volume resuscitation consider:
- Central venous pressure monitoring
- Mixed venous sampling

Ed Treatment/Procedures

Incision and drainage are the mainstays of treatment.
- Incision should be deep enough to allow adequate drainage
- Elliptical incision prevent early closure
- Break loculations with gentle exploration
- Irrigate cavity after expressing all pus
Loose packing of abscess cavity when:
- Larger than 5 cm
- Comorbid medical conditions
- HIV
- Diabetes
- Malignancy
- Chronic steroid use
- Immunosuppressed
- Abscess location: face, neck, scalp, hands/feet, perianal, perirectal, genital
- Promote drainage and prevent premature closure
For simple cutaneous abscesses (<5 cm) packing may not be routinely indicated.
Routine antibiotics are not indicated.
Antibiotics are indicated for the following conditions:
- Sepsis/systemic illness
- Facial abscesses drained into the cavernous sinus
- Concurrent cellulitis (see "Medication")
- Mammalian bites
- Immunocompromised hosts
Perirectal abscess requires treatment in the operating room
Hand infections that may require surgical intervention:
- Deep abscesses
- Fight bite abscesses
- Associated tenosynovitis/deep fascial plane infection
Loop drainage technique:
- Less invasive
- Simplifies wound care
- Procedure:
  - Anesthetize locally
  - Incision made at outer margin of abscess
  - Use a hemostat to break loculations and manually express pus
  - Use hemostat to localize distal margin of abscess and use as guide for a second incision
  - Grasp silicone vessel loop with hemostat and pull through and then gently tie
  - Patient should move loop daily to promote drainage
  - No repeat ED visits generally required
  - Removal in 7-10 days is painless

Incision and drainage are painful procedures that often require procedural sedation and analgesia.

Medication

Know your local susceptibility patterns
Oral antibiotics (moderate associated cellulitis):
- Amoxicillin/clavulanate:
  - Use: Mammalian bites/MSSA/Streptococcus species
  - Adult dose: 500-875 mg (peds: 40-80 mg/kg/d div q12h) PO q12h
- TMP-SMX:
  - Use: MRSA
  - Adult dose: 160/800 mg (peds: 4-5 mg/kg) PO BID
- Clindamycin:
  - Use: MRSA
  - Adult dose: 300-450 mg (peds: 4-8 mg/kg) PO q6h
- Doxycycline:
  - Use: MRSA
  - Adult dose: 100 mg (peds: over 8 yr: 1.1 mg/kg) PO q12h
- Cephalexin:
  - Use: MSSA/Strep species
  - Adult dose: 250 mg PO q6h or 500 mg PO q12h (peds: 25-50 mg/kg/d div q12h)
- Erythromycin:
  - Use: MSSA/Streptococcus species
  - Adult dose: 250-500 mg (peds: 10 mg/kg) PO q6-8h
IV antibiotics (systemic illness or extensive associated cellulitis):
- Ampicillin/sulbactam
  - Uses: Human/mammalian bites and facial cellulitis
  - Adult dose: 1.5-3 g (peds: <40 kg, 75 mg/kg; ≥40 kg, adult dose) IV q6h (max = 12 g/d)
- Vancomycin:
  - Use: MRSA
  - Adult dose: 15 mg/kg IV q12h (peds: 10-15 mg/kg/d div q6-8 h) (max. = 2,000 mg/d)
- Daptomycin:
  - Use MRSA
  - Adult dose: 4 mg/kg IV q24h
- Linezolid:
  - Use: MRSA
  - Adult dose: 600 mg IV/PO q12h (peds: 30 mg/kg/d div q8h)
- Clindamycin:
  - Use: MRSA
  - Adult dose: 600 mg (peds: 10-15 mg/kg) IV q8h

Follow-Up

Disposition

In accordance with abscess type and severity of infection
Admission Criteria

Sepsis/systemic illness
Immunocompromised host with moderate/large cellulitis
Perirectal involvement
Any abscess requiring incision and debridement in the operating room

Discharge Criteria
Most patients with uncomplicated abscesses can be treated with incision and drainage and close follow-up.

Follow-Up Recommendations

Recheck in 24-48 hr for packing removal and wound check.
Warm soaks for 2-3 days after packing removal

Pearls and Pitfalls

Consider CA-MRSA in recurrent abscesses
Pain control is essential during incision and drainage of abscesses
Beware of tenosynovitis and deep fascial space infections

Additional Reading

Alison DC, Miller T, Holtom P, et al. Microbiology of upper extremity soft tissue abscesses in injecting drug abusers. Clin Orth Related Res. 2007;461:9-13.
Buescher ES. Community-acquired methicillin-resistant Staphylococcus aureus in pediatrics. Curr Opin Pediatr. 2005;17:67-70.
Hankin A, Everett W. Are antibiotics necessary after incision and drainage of a cutaneous abscess? Ann Emerg Med. 2007;50:49-51.
Ladd AP, Levy MS, Quilty J. Minimally invasive technique in treatment of complex, subcutaneous abscesses in children. J Pediatr Surg. 2012:45:1562-1566.
O'Malley GF, Dominici P, Giraldo P, et al. Routine packing of simple cutaneous abscesses is painful and probably unnecessary. Acad Emerg Med. 2009;16:470-473.
Tayal V, Hasan N, Norton HJ, et al. The effect of soft-tissue ultrasound on the management of cellulitis in the emergency department. J Acad Emer Med. 2006;13:384-388.
Tsoraides SS, Pearl RH, Stanfill AB, et al. Incision and loop drainage: A minimally invasive technique for subcutaneous abscess management in children. J Pediatr Surg. 2012;45:606-609.

Codes

ICD9

566 Abscess of anal and rectal regions
682.9 Cellulitis and abscess of unspecified sites
685.0 Pilonidal cyst with abscess
680.9 Carbuncle and furuncle of unspecified site
705.83 Hidradenitis

ICD10

K61.0 Anal abscess
L02.91 Cutaneous abscess, unspecified
L05.01 Pilonidal cyst with abscess
L02.92 Furuncle, unspecified
L02.93 Carbuncle, unspecified
L02.9 Cutaneous abscess, furuncle and carbuncle, unspecified
L73.2 Hidradenitis suppurativa

SNOMED

128477000 Abscess (disorder)
200714005 Pilonidal sinus with abscess (disorder)
82127005 perianal abscess (disorder)
416675009 furuncle (disorder)
416893007 Carbuncle (disorder)
59393003 hidradenitis suppurativa (disorder)

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