Is it normal for a previously infected epidermoid cyst to still have a drainage crust 4.5 weeks after incision and drainage (I&D) with packing?

Ongoing Drainage at 4.5 Weeks Post-I&D: Assessment and Management

Some drainage and crust formation at 4.5 weeks after incision and drainage of an infected epidermoid cyst is abnormal and suggests either incomplete drainage, retained cyst wall, or ongoing inflammation that requires clinical evaluation.

Understanding Normal Healing Timeline

• After proper incision and drainage with adequate evacuation of contents, most wounds should heal within 2-3 weeks with simple dry dressing changes 1
• Persistent drainage beyond this timeframe indicates a problem with the initial treatment or wound healing process 1, 2

Most Likely Causes of Persistent Drainage

Inadequate initial drainage is the most common cause of treatment failure and recurrence:

• The cavity may not have been thoroughly evacuated of all purulent material during the initial I&D 1, 2
• Loculations or septations within the cyst may not have been broken up by probing the cavity 1, 2
• Incomplete removal or retained portions of the cyst wall can lead to ongoing inflammation and drainage 3, 4

Retained foreign material or cyst contents:

• The cyst wall itself acts as a foreign body if not completely removed, perpetuating inflammation 4
• For recurrent problems at the same site, search for retained foreign material 1

Clinical Assessment Required

Evaluate for signs that would indicate need for intervention:

• Systemic signs of infection: temperature >38°C or <36°C, tachycardia >90 bpm, tachypnea >24 breaths/min, or WBC >12,000 or <400 cells/µL 5, 1
• Local signs: expanding erythema >5 cm from the incision, induration, necrosis, or purulent drainage 5
• Wound characteristics: size of drainage area, presence of fluctuance suggesting re-accumulation 2

Recommended Management Approach

For persistent drainage without systemic signs:

• Re-open the incision and ensure complete evacuation of all contents 1
• Probe the cavity thoroughly to break up any loculations or septations 1, 2
• Cover with dry sterile dressing rather than packing with gauze, as packing causes more pain without improving healing 1, 2

Antibiotic therapy is indicated only if:

• Systemic inflammatory response is present 5, 1, 2
• Extensive surrounding cellulitis (>5 cm erythema with induration) 5
• Patient is immunocompromised or has markedly impaired host defenses 5, 1, 2
• If antibiotics are needed, use agents active against Staphylococcus aureus (dicloxacillin for MSSA, clindamycin for MRSA) 1, 2

Definitive Treatment Consideration

Once acute inflammation resolves, consider complete excision:

• Definitive treatment requires surgical removal of the entire cyst with its wall to prevent recurrence 3, 4
• A delayed approach (5-7 days after drainage, then excision with delayed primary closure) has shown good outcomes with average recovery of 18.6 days and no recurrence 4
• Complete removal of the cyst wall is essential to avoid relapses 3

Common Pitfalls to Avoid

• Do not assume ongoing drainage is normal healing - this timeframe suggests inadequate initial treatment 1, 2
• Do not prescribe antibiotics without addressing the mechanical problem - antibiotics alone without adequate drainage will fail 2
• Do not close the wound without ensuring complete drainage - this leads to recurrent infection 1
• Do not pack the wound unnecessarily - this increases pain without improving outcomes 1