A cutaneous abscess is a collection of pus within the dermis and deeper skin tissues, most commonly caused by Staphylococcus aureus (including MRSA). Incision and drainage (I&D) is the cornerstone of treatment, with adjunctive antibiotics reserved for select patients. [1-2]
1. History
- Onset and duration of swelling, pain, erythema; rate of progression
- Inciting event: skin trauma, insect bite, ingrown hair, injection drug use, recent shaving
- Prior abscesses: frequency, locations, prior cultures (MRSA vs MSSA), prior treatments
- Symptom characterization: pain severity, warmth, spontaneous drainage, fevers/chills/rigors
- Associated symptoms: red streaking (lymphangitis), malaise, myalgias
- Important negatives: no crepitus, no rapidly spreading erythema, no pain out of proportion to exam (necrotizing fasciitis mimics)
- Immunosuppression screen: diabetes, HIV, chemotherapy, chronic steroids, transplant
2. Alarm Features
- SIRS criteria: temperature >38°C or <36°C, HR >90, RR >24, WBC >12,000 or <4,000 [1]
- Hypotension — suggests severe/septic presentation requiring IV antibiotics and possible admission [1]
- Rapidly spreading erythema, crepitus, pain out of proportion → concern for necrotizing fasciitis [3]
- Dusky/necrotic skin, bullae, or hemorrhagic changes
- Location over major vessels/nerves (groin, neck, antecubital fossa) — risk of pseudoaneurysm in IVDU; use Doppler ultrasound before incision [4]
- Facial abscesses (risk of cavernous sinus thrombosis)
- Perianal/perirectal abscess with systemic toxicity
- Immunocompromised host with any abscess
3. Medications
- Adjunctive antibiotics post-I&D (when indicated):
- TMP-SMX DS 1–2 tabs PO BID × 7–10 days (preferred first-line for MRSA coverage) [5]
- Clindamycin 300–450 mg PO TID × 7–10 days (alternative; higher adverse event rate but lower recurrence) [5]
- Doxycycline 100 mg PO BID × 7–10 days (alternative; avoid in children <8 years) [5]
- Severe/systemic infection: IV vancomycin, daptomycin, or linezolid [1]
- Contraindicated/low-yield: Cephalexin alone is inadequate for MRSA-positive abscesses — patients prescribed cephalexin had significantly higher treatment failure and repeat I&D rates compared to TMP-SMX or clindamycin [6]
- Cautions: TMP-SMX — hypersensitivity reactions, hyperkalemia, renal dosing; clindamycin — C. difficile risk [5]
4. Diet
- No specific dietary triggers or restrictions
- Adequate hydration, especially if febrile or on TMP-SMX
- Optimize glycemic control in diabetic patients to reduce recurrence risk [7]
5. Review of Systems
- Constitutional: fevers, chills, rigors, malaise, night sweats
- Skin: other boils, draining lesions, rashes, chronic wounds
- MSK: joint pain/swelling near abscess (septic joint/osteomyelitis concern)
- Vascular: IV drug use sites, track marks, signs of endocarditis (new murmur, splinter hemorrhages)
- GI: perianal pain, drainage, change in bowel habits (Crohn's-associated perianal abscess)
- GU: groin/labial swelling (Bartholin abscess)
6. Collateral History and Family History
- Household contacts with recurrent boils or MRSA infections — household decolonization may be needed [1][8]
- Close-contact settings: athletes, military, incarcerated individuals, daycare [9]
- Family history of recurrent abscesses beginning in childhood → evaluate for neutrophil disorders (e.g., chronic granulomatous disease, hyper-IgE syndrome) [1]
- Social history: IVDU (polymicrobial flora with streptococci and anaerobes more common), homelessness, crowded living conditions [10]
7. Risk Factors
- S. aureus nasal/skin colonization (especially MRSA) [9][11]
- IVDU — abscesses more likely polymicrobial with streptococci and anaerobes [10]
- Diabetes mellitus, obesity, immunosuppression [7]
- Prior SSTI (strongest predictor of recurrence) [7-8]
- Skin disruption: shaving, insect bites, abrasions, eczema [3][9]
- Close-contact environments, poor hygiene
- Smoking, alcoholism [12]
- Delay in treatment of cellulitis [12]
8. Differential Diagnosis
- Cellulitis without abscess — no fluctuance; POCUS differentiates [13]
- Inflamed epidermoid (inclusion) cyst — central punctum, cheesy keratinous material; inflammation is a foreign-body reaction, not true infection [1]
- Hidradenitis suppurativa — recurrent abscesses in intertriginous areas (axillae, groin, inframammary); I&D has high recurrence, excision preferred [14]
- Pilonidal cyst/abscess — sacrococcygeal location
- Necrotizing fasciitis — pain out of proportion, crepitus, rapid spread, systemic toxicity; cannot-miss diagnosis [4]
- Mycobacterial or fungal infection — indolent, non-healing, travel history
- Vascular pseudoaneurysm — pulsatile mass, especially in groin of IVDU; always use Doppler before incision [4]
- Foreign body granuloma
- Soft tissue tumor (lipoma, sarcoma) — non-tender, non-erythematous [12]
- Bartholin gland abscess (vulvar location)
9. Past Medical History
- Prior abscesses: number, locations, cultures, treatments, recurrence pattern
- Diabetes, HIV/AIDS, malignancy, organ transplant, chronic steroid use
- Crohn's disease (perianal abscesses)
- Hidradenitis suppurativa
- Prosthetic devices (valves, joints) — consider endocarditis risk with bacteremia
- Surgical history at abscess site (surgical site infection)
- History of MRSA colonization or infection
10. Physical Exam
- Inspection: erythema, swelling, pointing/pustule, spontaneous drainage, skin necrosis, crepitus, lymphangitis (red streaking)
- Palpation: fluctuance (hallmark finding), warmth, tenderness, induration
- Vital signs: fever, tachycardia, hypotension → SIRS/sepsis [1]
- Size measurement: document diameter; >5 cm historically associated with higher hospitalization risk in children [2]
- Surrounding cellulitis: mark borders with skin marker to track progression
- Regional lymphadenopathy
- Focused exam maneuvers: assess for crepitus (necrotizing fasciitis), pulsatility (pseudoaneurysm), central punctum (epidermoid cyst)
11. Lab Studies
- Routine uncomplicated abscess: labs generally unnecessary [1]
- Wound culture: Gram stain and culture of purulent drainage recommended by IDSA, though treatment without culture is reasonable in typical cases [1]
- When systemically ill:
- CBC with differential (leukocytosis or leukopenia)
- BMP (renal function if starting TMP-SMX)
- Blood cultures (if SIRS, sepsis, immunocompromised, or concern for endocarditis)
- Lactate, CRP/ESR if concern for deeper infection
- Recurrent abscesses in childhood: evaluate for neutrophil disorders (DHR flow cytometry for CGD, immunoglobulin levels) [1]
12. Imaging
- First-line: Point-of-care ultrasound (POCUS)[4][13]
The following figure from Singer and Talan (NEJM, 2014) demonstrates the classic ultrasonographic appearances of abscess versus cellulitis:
- POCUS also identifies: loculations, abscess depth/margins, nearby vasculature (use color Doppler to rule out pseudoaneurysm) [4]
- CT with contrast: reserved for deep/complex abscesses (perirectal, retroperitoneal, neck) or concern for necrotizing fasciitis
- MRI: rarely needed; consider for spinal epidural abscess or deep fascial plane infections
- Imaging unnecessary for small, superficial, clearly fluctuant abscesses
13. Special Tests
- POCUS (as above) — the most impactful special test in the ED for this condition [13][15]
- LRINEC score: if necrotizing fasciitis is a concern (WBC, hemoglobin, sodium, glucose, creatinine, CRP)
- Needle aspiration: generally not recommended as definitive treatment (only 26% success rate vs 80% for I&D), but can be used diagnostically or for culture [1-2]
- Incision and drainage is both diagnostic and therapeutic
14. ECG
- Not routinely indicated
- Obtain if: IVDU with systemic signs (endocarditis concern), sepsis, significant tachycardia, or hemodynamic instability
- No specific ECG patterns associated with cutaneous abscess
15. Assessment
Cutaneous abscesses are classified by the IDSA into severity tiers: [1]
- Mild: no SIRS criteria → I&D alone is sufficient
- Moderate: SIRS criteria present → I&D + oral antibiotics with MRSA activity
- Severe: SIRS + hypotension or immunocompromised → I&D + IV antibiotics, consider admission
S. aureus (including MRSA) is the dominant pathogen, isolated in ~67% of cases; MRSA specifically in ~49%. [5] IVDU-associated abscesses are more polymicrobial with streptococci and anaerobes. [10] Recurrence rates range from 7–45% depending on risk factors. [7]
16. Treatment Plan
Initial stabilization
Incision and drainage (primary treatment): [1-2]
- Local/regional anesthesia (consider procedural sedation for large abscesses, children, or sensitive areas) [2]
- Incision along skin tension lines, long enough for complete drainage
- Break up loculations with blunt instrument (hemostat)
- Irrigate cavity
- Packing: recent evidence supports abandoning routine packing — it increases pain without improving outcomes; simple dry dressing is preferred [1][16]
- Loop drainage: an alternative technique (two stab incisions with a vessel loop threaded through) — preferred in pediatrics, less painful, avoids packing, comparable efficacy [2][17]
The following figure illustrates loop drainage and primary closure techniques:
Adjunctive antibiotics: [5]
A landmark placebo-controlled trial (Daum et al., NEJM 2017) demonstrated that both clindamycin and TMP-SMX improved cure rates over placebo (83.1% and 81.7% vs 68.9%) when added to I&D for abscesses ≤5 cm. [5]
Recurrence prevention: [1]
- 5-day decolonization: intranasal mupirocin BID + daily chlorhexidine washes + decontamination of personal items (towels, sheets, razors)
- Include household contacts in decolonization [8]
- Dilute bleach baths (¼–½ cup per full bath) as alternative to chlorhexidine
17. Disposition
Discharge criteria (majority of patients): [2][17]
- Uncomplicated abscess successfully drained
- No SIRS criteria or systemic toxicity
- Able to tolerate oral antibiotics (if indicated)
- Reliable follow-up
Admission criteria
- SIRS with hypotension / sepsis [1]
- Failed outpatient I&D or worsening despite antibiotics
- Significant immunocompromise with systemic signs
- Abscess requiring operative drainage (large, deep, complex, or in sensitive location — hand, face, perirectal) [2]
- Concern for necrotizing fasciitis or deeper space infection
- Inability to tolerate oral medications or unreliable follow-up
Specialist consultation triggers
- Hand, facial, or perianal/perirectal abscesses → surgery
- Suspected necrotizing fasciitis → emergent surgical consultation
- Recurrent abscesses → infectious disease or immunology (if childhood onset) [1]
18. Follow Up / Return Precautions
- Follow-up: wound check in 48–72 hours for reassessment; remove packing if placed
- If no packing: follow-up in 1–2 weeks or sooner if worsening
- Return precautions — return immediately for:
- Worsening redness, swelling, or pain
- Fever, chills, or feeling systemically unwell
- Red streaking from the wound
- Wound not improving after 48 hours
- Patient counseling:
- Keep wound clean and dry; change dressings as instructed
- Complete full antibiotic course if prescribed
- Do not squeeze or manipulate the wound
- Warm compresses may help with residual induration
- Hygiene measures: frequent handwashing, avoid sharing towels/razors, launder linens in hot water
- Expected recovery: most uncomplicated abscesses heal within 1–2 weeks after adequate drainage [16]
- Recurrence: occurs in 7–45% of patients; prior SSTI is the strongest predictor [7-8]
References
1. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America. — Stevens DL, Bisno AL, Chambers HF, et al. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2014.
2. Management of Skin Abscesses in the Era of Methicillin-Resistant Staphylococcus aureus. — Singer AJ, Talan DA. The New England Journal of Medicine. 2014.
3. Guide to Utilization of the Microbiology Laboratory for Diagnosis of Infectious Diseases: 2024 Update by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM). — Miller JM, Binnicker MJ, Campbell S, et al. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2024.
4. Ultrasound Guidelines: Emergency, Point-of-Care, and Clinical Ultrasound Guidelines in Medicine. — American College of Emergency Physicians (2023). 2023.
5. A Placebo-Controlled Trial of Antibiotics for Smaller Skin Abscesses. — Daum RS, Miller LG, Immergluck L, et al. The New England Journal of Medicine. 2017.
6. Antibiotic Prescribing and Outcomes for Patients With Uncomplicated Purulent Skin and Soft Tissue Infections in the Emergency Department. — Ibrahim T, Thompson C, Borgundvaag B, McLeod SL. Cjem. 2022.
7. Recurrence of Skin and Soft Tissue Infections: Identifying Risk Factors and Treatment Strategies. — Toschi A, Giannella M, Viale P. Current Opinion in Infectious Diseases. 2025.
8. Evaluating Personal and Environmental Decolonization Strategies for Children With Skin and Soft Tissue Infection and Their Households - A Randomized Clinical Trial. — Robinson AL, Boyle MG, Hogan PG, et al. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2025.
9. Post-Travel Dermatologic Conditions. — Karolyn A. Wanat and Scott A. Norton CDC Yellow Book. 2025.
10. Microbiology and Initial Antibiotic Therapy for Injection Drug Users and Non-Injection Drug Users With Cutaneous Abscesses in the Era of Community-Associated Methicillin-Resistant Staphylococcus Aureus. — Jenkins TC, Knepper BC, Jason Moore S, et al. Academic Emergency Medicine : Official Journal of the Society for Academic Emergency Medicine. 2015.
11. Staphylococcal Decolonisation: An Effective Strategy for Prevention of Infection?. — Simor AE. The Lancet. Infectious Diseases. 2011.
12. Soft Tissue Masses: Evaluation and Treatment. — Achar S, Yamanaka J, Oberstar J. American Family Physician. 2022.
13. Point-of-Care Ultrasonography for the Diagnosis Of Skin and Soft Tissue Abscesses: A Systematic Review and Meta-Analysis. — Gottlieb M, Avila J, Chottiner M, Peksa GD. Annals of Emergency Medicine. 2020.
14. Abscess Management: An Evidence-Based Review for Emergency Medicine Clinicians. — Menegas S, Moayedi S, Torres M. The Journal of Emergency Medicine. 2021.
15. What Is the Utility of Point-of-Care Ultrasound for Diagnosis of Soft Tissue Abscess vs. Cellulitis?. — Jeffers K, Keim SM, Long B, Gottlieb M, Adhikari SR. The Journal of Emergency Medicine. 2025.
16. Beyond the Knife: A Contemporary Review of Subcutaneous Abscesses. — Mersal M, Embaby O, Ayyad M, et al. ANZ Journal of Surgery. 2025.
17. Diagnosis and Management of Cellulitis and Abscess in the Emergency Department Setting: An Evidence-Based Review. — Long B, Gottlieb M. The Journal of Emergency Medicine. 2022.