Skin abscess

Disease Description (Causes and Symptoms)

• Definition: A localized abscess (fluctuant mass) caused by pus accumulating in the skin or subcutaneous tissue.
• Causes and pathophysiology: When bacteria enter the skin through a wound, hair follicle, sweat gland, or penetrating foreign body, a localized inflammatory response occurs. White blood cells (mainly neutrophils) fight the bacteria, and dead cells, bacteria, proteins, and other materials accumulate to form pus. The most common pathogen is Staphylococcus aureus; MRSA may be the cause in areas with regional MRSA prevalence.
• Main symptoms: Localized swelling, tenderness, redness, warmth, firmness or fluctuance at the center, and pus drainage. Systemic symptoms such as fever and tachycardia or spreading erythema around the area (severe cellulitis) may indicate a systemic infection. Enlarged lymph nodes may also occur.
• Risk factors: Diabetes, immunosuppression, steroid use, obesity, skin injury, foreign bodies, prolonged friction, sweating, tight clothing, and a history of previous MRSA infection.

Treatment Methods (Standard Treatment · Medications · Procedures/Surgery · Lifestyle Management and Precautions)

• Basic principle: The first-line treatment for a simple cutaneous abscess is incision and drainage (I&D). Once drainage of the pus is confirmed, most cases improve with this treatment alone (without antibiotics).
• Criteria for antibiotic use: Antibiotics are recommended in addition to drainage when there are systemic symptoms (fever, tachycardia, or generalized weakness), extensive surrounding cellulitis, multiple abscesses, immunocompromised status (diabetes or immunosuppressive treatment), risk factors for infective endocarditis or endovascular infection such as endocarditis or a prosthetic valve, severe pain, or a large abscess. Healthy adults with a simple localized abscess often do not need antibiotics after I&D.
• Empirical antibiotics (selected according to local resistance rates and the patient's condition):
  • Outpatient oral treatment (mild to moderate cases, considering MRSA risk): trimethoprim-sulfamethoxazole (TMP-SMX), doxycycline, or clindamycin (considering the local clindamycin resistance rate). Penicillin agents alone do not provide comprehensive coverage.
  • Inpatient·severe cases (intravenous): Select MRSA-targeted treatments such as vancomycin, daptomycin, or linezolid (according to hospital policy and susceptibility results).
• Diagnostic support and procedure-related care:
  • During aspiration or drainage, collect the drainage for culture and Gram staining (especially in recurrent or severe cases or when antibiotic selection is needed).
  • High-frequency ultrasound can be used to check for the presence and extent of an abscess (useful when it is not visible on radiographs).
  • Pain relief and inflammation control: Apply warm compresses to promote abscess maturation and use analgesics.
  • Wound care: Apply wound dressings after drainage and, if necessary, pack the wound (whether to use packing for a large cavity is a clinical decision). Maintain disinfection and cleanliness.
  • Hospitalization and surgical evaluation may be necessary in cases of deep tissue involvement, abscesses in high-risk areas such as the face (around the eyes), neck, or perianal region, signs of sepsis, or extensive tissue destruction.
  • Vaccination/prevention: If related to a wound, check tetanus vaccination status.
• Precautions and risk of complications:
  • Never squeeze the abscess or attempt self-incision at home (risk of worsening infection, bleeding, and wound extension).
  • Complications: Spread of cellulitis, sepsis, recurrent abscess, and, rarely, scarring, perforation (depending on the location), or formation of a deep tissue abscess.
  • Special considerations: Antibiotic prophylaxis may be considered for high-risk patients with a history of endocarditis, a prosthetic valve, or similar conditions; therefore, the medical history must be checked before treatment.
  • Recurrence prevention: Improve personal hygiene (regular showers/baths), avoid excessive friction, prolonged driving, and tight clothing, manage body weight (obesity has been reported as a related factor), manage wounds promptly, and do not share commonly used items such as razors.

Checklist Before an Outpatient Visit (Including Items to Bring · Things to Check Before the Visit · Example Questions)

• Items/materials to bring:
  • List of currently used medications (including antibiotics, anticoagulants, steroids, and immunosuppressants)
  • Records of past medical conditions (diabetes, history of endocarditis, prosthetic valve, etc.) and surgical history
  • Recent temperature and symptom changes (onset, degree of pain, changes in size) and photographs (if possible, take them at regular intervals)
  • Previous culture test or treatment records (whether previously positive for MRSA)
• Things to check before the visit:
  • Whether systemic symptoms such as fever, chills, or rapid worsening are present
  • Whether you attempted to squeeze the abscess yourself and the result (bleeding, enlargement, etc.)
  • Whether you are taking anticoagulants (warfarin, NOACs, etc.)
• Example questions (questions patients can prepare in advance):
  • When did it first appear, and how have its size and pain changed?
  • Have you recently had a fever or chills?
  • Are you currently taking any medications, or do you have any allergies (especially to antibiotics)?

Examples of General Questions to Ask the Doctor

• "Does this abscess require incision and drainage, or should I start antibiotics first?"
• "What are the side effects of the recommended antibiotic, and how long should I take it?"
• "What daily care should I follow to reduce the risk of recurrence?"

Examples of Disease-Specific Questions (1–2)

• "I have diabetes (or am immunosuppressed). In this case, are antibiotics or inpatient treatment recommended?"
• "I previously tested positive for MRSA. Does this affect the choice of empirical antibiotics for this abscess?"

(Note: Diagnosis and treatment vary according to each patient's condition, so the final decision and prescription should follow the doctor's judgment based on a medical consultation.)