Epidermal Inclusion Cyst

Epidermoid Cyst / Sebaceous Cyst

Overview

Epidermal inclusion cysts (often called epidermoid cysts or incorrectly "sebaceous cysts") are very common, benign, slow-growing nodules beneath the skin surface. They form when surface skin cells become trapped below the surface and produce keratin, creating a cyst wall and central contents. They may become inflamed or infected, causing pain and swelling.

Key Symptoms

  • Firm, round, mobile nodule under the skin
  • Skin-colored to slightly yellowish
  • Often has a visible central punctum (small dark pore)
  • Typically 1-5 cm in diameter, can grow larger
  • Painless unless inflamed or infected
  • May express thick, cheese-like, foul-smelling keratin material if ruptured

Affected Areas

Face, Neck, Trunk, Behind ears, Back, Scalp

Care Instructions

  1. No treatment is needed for asymptomatic cysts.
  2. Do NOT squeeze or attempt to pop the cyst — this can cause infection and scarring.
  3. Apply warm compresses if the cyst becomes inflamed.
  4. See a dermatologist if the cyst becomes painful, red, swollen, or rapidly enlarging.
  5. Complete surgical excision (including the cyst wall) is the only definitive treatment to prevent recurrence.
  6. If infected, antibiotics or incision and drainage may be needed before definitive excision.

Medical Disclaimer: This information is for educational purposes only and does not replace professional medical advice. Always consult a qualified dermatologist for diagnosis and treatment.

Prevalence: Very common; one of the most frequently encountered skin cysts