International Academy of Cosmetic Dermatology
KERATINOUS CYST
A keratinous cyst is the most common kind of epidermal cyst and is filled with keratin originating from the epidermis, most often from a hair follicle. Once called a sebaceous cyst, it arises spontaneously and is prone to rupture. It is most commonly found on the trunk, nape, and behind the ears. When a cyst appears on the scalp, it is most commonly a trichilemmal cysts or wen.
It present as a dome-shaped, slightly mobile, elevated nodule, ranging from 0.5-5.0 cm in size. If inflamed, it may appear red and boggy, being tender to palpation. When drained, thick cheesy keratin debris along with purulent material can sometimes be expressed. This is often foul smelling.
| Once the surrounding sac is interrupted either by trauma or by bacterial infection, the cyst dissipates. Thus, there can be several types of treatment: |
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Robert A. Norman, DO, MPH
Tampa, FL, USA