Epidermal Inclusion Cyst
An epidermal inclusion cyst is a small, benign lump that forms under the skin, often filled with keratin, a protein found in skin cells. These cysts can develop anywhere on the body and usually grow slowly. They are generally painless, though they can become red, tender, or infected. Treatment is often not necessary, but cysts causing discomfort or cosmetic concern can be removed surgically.
Overview | Symptoms & Causes | Diagnosis | Treatment Options
What is an Epidermal Inclusion Cyst?
Epidermal inclusion cysts are common, benign lumps that form just under the skin. They occur when skin cells multiply in a confined area rather than naturally shedding, creating a small sac filled with keratin, a protein normally found in skin, hair, and nails.
These cysts can appear anywhere on the body but are most frequently found on the face, neck, back, or trunk. They usually feel firm or rubbery, move slightly under the skin, and may have a small central opening or punctum. Most epidermal cysts grow slowly and are painless, though they can become red, tender, or infected in some cases.
Understanding Epidermal Inclusion Cysts
Epidermal inclusion cysts are generally harmless and often discovered incidentally. While most remain small and painless, they can sometimes cause discomfort or other noticeable changes.
Common features include:
- A small, firm, round lump just beneath the skin.
- Slow growth over time, though size can vary.
- Occasionally a visible central punctum (small opening) on the surface.
- Tenderness, redness, or swelling if the cyst becomes inflamed or infected.
- Rarely, fluid or cheesy material may drain from the cyst.
These cysts are usually not dangerous, but any rapid growth, persistent pain, or signs of infection should prompt a medical review.
Causes & Risk Factors
Epidermal inclusion cysts form when skin cells that normally shed from the surface get trapped under the skin, continuing to grow and produce keratin. Common causes and risk factors include:
| Skin trauma | Cuts, surgical wounds, or other injuries can trap skin cells beneath the surface, leading to cyst formation. |
| Blocked hair follicles or sebaceous glands | Blockages in these areas can cause cysts, commonly on the face, neck, or trunk. |
| Genetic predisposition | Some individuals are more prone to developing multiple cysts. |
| Underlying skin conditions | Conditions such as acne or chronic skin irritation may increase the likelihood of cyst formation. |
Most cysts appear without a clear cause and are generally harmless, though they can become inflamed or infected.
Diagnosing an Epidermal Inclusion Cyst
Diagnosis is usually straightforward and based on a physical examination, as these cysts often have a characteristic appearance and feel.
| Clinical Examination | A healthcare provider will assess the lump’s size, texture, and mobility. Epidermal inclusion cysts are typically smooth, round, and firm, with a visible central punctum in some cases. |
| Ultrasound | Ultrasound can help confirm the cyst is fluid- or keratin-filled and rule out other types of lumps or masses. This is usually only required if the cyst is unusually large, deep, or in an atypical location. |
Treatment Options
Most epidermal inclusion cysts are harmless and do not require treatment unless they cause discomfort, become inflamed, or for cosmetic reasons.
| Observation | Many cysts remain stable and can be safely observed without intervention. |
| Minimally invasive procedures | If the cyst becomes painful or infected, a healthcare provider may perform a small drainage or incision to relieve pressure, though this does not always remove the cyst completely. |
| Surgical removal | Complete excision of the cyst and its capsule is the only way to prevent recurrence. This is often done under local anesthesia by a specialist. |
How can Lanthorn help?
Lumps & Bumps Ultrasound - £300
A quick, non-invasive scan that can confirm the presence of an epidermal inclusion cyst, show its size and exact location, and help distinguish it from other types of lumps.
Referral to a specialist
If the cyst requires further management or removal, we can provide a referral to a specialist for assessment and appropriate treatment.
