What is the treatment for a patient presenting with an inflamed cyst?

Treatment of Inflamed Cysts

Incision and drainage is the primary treatment for an inflamed cyst, with antibiotics reserved only for patients showing systemic signs of infection. 1, 2

Primary Management: Incision and Drainage

• Perform incision and drainage with thorough evacuation of all purulent material as the cornerstone of treatment. 1, 2 This provides immediate relief and addresses the mechanical problem causing symptoms.

• Probe the cavity thoroughly to break up any loculations or septations to ensure complete drainage. 1, 2 This critical technical step prevents treatment failure from inadequate drainage.

• Cover the surgical site with a simple dry dressing after drainage. 1, 2 Studies demonstrate this approach is effective for wound healing.

• Do not pack the wound with gauze—it increases pain without improving healing outcomes. 1, 2 This is a common pitfall that should be avoided.

Understanding the Pathophysiology

• The inflammation in sebaceous cysts typically results from rupture of the cyst wall with extrusion of contents into the dermis, rather than primary bacterial infection. 1, 2 This explains why drainage alone is usually sufficient without antibiotics.

• Research shows that 47% of cultured inflamed cysts result in no bacterial growth or only normal flora. 3 This high rate of culture negativity supports the conservative approach to antibiotic use.

Antibiotic Indications

Systemic antibiotics are unnecessary unless the patient demonstrates signs of systemic infection or has markedly impaired host defenses. 1, 2

• Prescribe antibiotics only when the patient has:

  • Temperature >38°C or <36°C 1, 2
  • Tachypnea >24 breaths per minute 1, 2
  • Tachycardia >90 beats per minute 1, 2
  • White blood cell count >12,000 or <4,000 cells/µL 1, 2

• When antibiotics are indicated, choose agents active against Staphylococcus aureus, the most common pathogen. 1, 2 Consider local MRSA prevalence when selecting specific agents.

• Gram stain and culture of pus are not routinely recommended unless there are specific clinical indications. 1, 2

Management of Persistent or Inadequate Drainage

• If the infection persists or worsens after initial drainage, re-open the incision and ensure complete evacuation of all contents. 1, 4, 2 Incomplete drainage is the most common cause of treatment failure.

• Thoroughly probe the cavity again to break up any remaining loculations and ensure all purulent material is evacuated. 1, 4, 2

• Most wounds should heal within 2-3 weeks with proper drainage and simple dressing changes. 4 Persistent drainage beyond this timeframe indicates inadequate initial treatment.

Prevention of Recurrence

• For recurrent infections at the same site, search for local causes such as retained foreign material or incomplete cyst wall removal. 1, 2

• Consider complete excision of the cyst and its wall once acute inflammation has resolved to prevent future episodes at the same location. 1, 2

• One-stage excision of inflamed sebaceous cysts (when appropriately selected) decreases antibiotic exposure, reduces morbidity, and is more economical than conventional staged treatment. 5

Critical Pitfalls to Avoid

• Never close the wound without adequate drainage—this leads to recurrent infection. 1, 2

• Do not routinely prescribe antibiotics in the absence of systemic infection signs. 1, 2 Despite high prescription rates (84-94% of physicians prescribe antibiotics), 6 this practice is not supported by evidence given the high rate of culture negativity.

• Avoid wound packing—it increases pain without benefit. 1, 2

• Do not perform routine cultures unless there are specific clinical indications. 1, 2

• Do not assume ongoing drainage beyond 2-3 weeks is normal healing—this indicates inadequate initial treatment requiring re-intervention. 4