EpistemisEpidermoid cysts
Specialty: Skin.
Why it occurs
- Proliferation of epidermal cells within the dermis secondary to the implantation of epidermal epithelium due to microtrauma
- Mechanical obstruction of the follicular infundibulum (common in acne vulgaris)
- Genetic anomalies of ectodermal development (associated with Gardner syndrome if they occur multiple times)
- Use of immunomodulatory or acne-inducing chemotherapy drugs
- Local microtrauma due to repetitive shaving or hair removal.
Initial workup
Eminently clinical diagnosis of a mobile subcutaneous nodule with a characteristic central keratotic pore. High-resolution ultrasound of soft tissues of the skin to confirm the delimited anechoic or hypoechoic cystic nature, without internal Doppler flow, ruling out vascular malformations or liposarcomas.
red flags
Spontaneous intracutaneous rupture of the cyst with extreme acute pain, extensive violaceous erythema on the periphery of the lesion, local heat and fetid purulent suppuration (inflammatory reaction to a foreign body due to keratin that simulates active bacterial infection and requires immediate drainage), or rapid asymmetric growth that raises suspicion of malignancy.
Standard management
- Intralesional injection of triamcinolone acetonide — 2 to 5 mg inside the non-infected inflamed cystic wall to quickly reduce acute symptoms
- Cephalexin — oral antibiotic indicated only if there is confirmation of cellulitis or associated secondary bacterial infection, dose of 500 mg every 6 hours for 7 days
- Ibuprofen to control pain and inflammation of the keratin reaction
- Referral to minor surgery for complete excision of the cyst including the keratinizing capsule once the acute inflammatory phase has completely subsided.
Educational guidance for study. It is NOT a prescription recommendation. The actual choice depends on the cause, the patient, and current guidelines.
- Area
- Skin
- Listed causes
- 5
- Treatment options
- 4