Sebaceous Cysts: Symptoms, Types, Causes and Treatment

Sebaceous cysts are common skin lumps that often cause concern due to their appearance or discomfort. Although frequently benign, these cysts can become inflamed, infected, or cosmetically bothersome, prompting many people to seek medical advice or removal. Understanding their symptoms, the various types, underlying causes, and available treatment options is crucial for informed decision-making and effective care.

Symptoms of Sebaceous Cysts

Sebaceous cysts typically manifest as painless, slow-growing lumps beneath the skin. While often harmless, their presence can be distressing, especially when located on visible areas like the scalp, face, or neck. Recognizing the range of symptoms can help distinguish sebaceous cysts from other skin conditions and determine when medical attention is necessary.

Symptom	Description	Commonality	Source(s)
Lump	Round, firm, movable nodule	Very common	2 3
Pain	Usually painless, but may ache if infected or inflamed	Occasional	2 3
Size	Varies (few mm to several cm)	Variable	2 3
Discharge	Oily/cheesy material if ruptured or pressed	Infected/ruptured cases	2 3
Redness	Red, warm skin if infected	Infected cases	2 3
Multiple	More than one cyst present, often on scalp/ears	Sometimes	2 3

Table 1: Key Symptoms

Common Presentations

Sebaceous cysts most often appear as round, mobile lumps under the skin, particularly on the scalp, face, neck, and sometimes the ears. They are usually not tender unless they become inflamed or infected 2 3. The skin over the cyst is typically normal but may become reddened and warm if infection occurs.

Signs of Complications

• Infection: When a cyst becomes infected, it may become painful, red, and swollen, sometimes with pus-like discharge 2 3.
• Rupture: Cysts can rupture, releasing an oily or cheesy material that can have an unpleasant odor 2.
• Multiple Cysts: Some individuals develop several cysts, especially on the scalp and behind the ears 2 3.

When to Seek Medical Attention

• Rapid growth
• Changes in color or shape
• Persistent pain or signs of infection
• Concerns about cosmetic appearance or suspicion of malignancy

Types of Sebaceous Cysts

Despite their common name, "sebaceous cysts" is a misnomer for most skin cysts. There are several types, each with unique characteristics, origins, and histological features. Understanding these distinctions is important for accurate diagnosis and treatment.

Type	Key Feature	Typical Locations	Source(s)
Trichilemmal	Derived from hair follicle (outer root sheath), filled with keratin	Scalp, ears	1 2 3
Epidermoid	Lined by epidermis-like cells, keratin-filled	Face, neck, trunk	2 4
Dermoid	Contains skin appendages (hair, glands) in lining	Embryonic fusion lines	2 4
Pilar (Pilar Cyst)	Subtype of trichilemmal, solid keratin, low malignancy risk	Scalp, face, back	3
Teratoid	Contains tissues from all three germ layers	Rare, head/neck exceptional	4

Table 2: Types of Sebaceous Cysts

Trichilemmal (Pilar) Cysts

Most so-called sebaceous cysts are actually trichilemmal (pilar) cysts. These arise from the outer root sheath of hair follicles and are filled with dense, non-fatty keratin 1 2. They are especially common on the scalp and may be multiple 1 2 3. Pilar cysts are a subtype, generally benign, but can rarely undergo malignant transformation 3.

Epidermoid Cysts

Epidermoid cysts are lined by stratified squamous epithelium and contain keratin with some sebaceous material. They often develop on the face, neck, or trunk and are sometimes congenital 2 4.

Dermoid Cysts

These are more complex, containing skin appendages like hair follicles, sebaceous, and sweat glands in their lining. Dermoid cysts typically arise along embryonic fusion lines and are usually congenital 2 4.

Teratoid Cysts

Extremely rare, teratoid cysts contain tissues from all three germ layers (ectoderm, mesoderm, endoderm). They are most commonly found in areas other than the head and neck, and are distinguished from teratomas by the absence of recognizable organ structures 4.

Causes of Sebaceous Cysts

Sebaceous cysts form due to a variety of factors, primarily involving the buildup of keratin or blockage of skin appendages. Although once thought to result from trapped sebaceous secretions, research has clarified several mechanisms behind their development.

Cause	Mechanism	Notes	Source(s)
Keratin Buildup	Accumulation in hair follicle or skin pore	Main cause, forms cyst wall	1 3
Follicular Blockage	Blocked hair follicle or sebaceous duct	Leads to cyst development	3 5
Genetic Predisposition	Familial tendency for multiple cysts	Especially pilar cysts	3
Embryonic Inclusion	Trapped skin elements during development	Explains dermoid/epidermoid	2 4
Inflammation/Trauma	Injury or inflammation leading to blockage	Sometimes a trigger	3 5
Abnormal Keratinization	Changes in skin cell differentiation	Seen in certain skin diseases	1 5
Environmental Toxins	Dioxin can activate pathways leading to cyst formation	Rare, specific conditions	5

Table 3: Causes of Sebaceous Cysts

Keratin Buildup and Follicular Blockage

The majority of sebaceous (trichilemmal/pilar) cysts result from the accumulation of keratin within the hair follicle or skin pore, often due to blockage at the follicular opening 1 3. This prevents normal expulsion of keratin, leading to cyst formation.

Genetic and Developmental Factors

• Genetic Predisposition: Some people, especially women, are more prone to developing multiple pilar (trichilemmal) cysts, suggesting a genetic component 3.
• Embryonic Inclusion: Dermoid and some epidermoid cysts are congenital, forming when skin elements become trapped during embryonic development 2 4.

Inflammation, Trauma, and Environmental Triggers

• Inflammation or Injury: In some cases, local trauma or chronic inflammation can block follicles or ducts, initiating cyst formation 3 5.
• Abnormal Keratinization: Certain skin disorders or changes in keratinocyte behavior can promote cyst development 1 5.
• Environmental Toxins: Rarely, exposure to substances like dioxin can activate cellular pathways (e.g., Nrf2) that lead to skin cysts, as seen in specific diseases like chloracne/MADISH 5.

Treatment of Sebaceous Cysts

Treatment for sebaceous cysts ranges from conservative management to surgical removal, depending on the cyst’s size, location, symptoms, and risk of infection or malignancy. Advances in minimally invasive techniques have improved cosmetic outcomes and reduced recovery times.

Treatment Type	Description	Best For	Source(s)
Conventional Excision	Wide removal of cyst and wall	Large, recurrent, ruptured, inflamed cysts	6 7 8
Minimal Excision	Small incision, remove cyst intact	Uninfected, facial, cosmetic areas	6 8
Punch Biopsy Excision	Circular blade removes cyst	Small cysts, rapid recovery	6 8
Laser-Assisted	Laser creates opening, staged wall removal	Large or thick-skinned areas	6
Pressing Method	Small opening, contents and sac expressed	Noninfectious, small cysts	10
Intraoral Approach	Removal via oral cavity to avoid skin scar	Lip/cheek cysts	9
Electrosurgery	High-frequency current destroys cyst	Select cases	10

Table 4: Treatment Options

Surgical Techniques

Conventional Excision

Wide excision removes both cyst and its entire capsule, minimizing recurrence but possibly leaving a larger scar. It is the preferred method for large, ruptured, or previously inflamed cysts 6 7 8.

Minimal Excision and Punch Biopsy

These methods use a small incision or punch to extract the cyst, leading to faster healing and minimal scarring. They are ideal for small, uninfected cysts in cosmetically sensitive areas, such as the face 6 8. However, if the cyst has ruptured, traditional excision is favored to ensure complete removal 8.

Laser-Assisted and Staged Excision

A newer approach involves using a laser to create a small hole to remove the cyst's contents, followed by excision of the cyst wall about a month later. This two-step method results in minimal scarring, making it especially useful for large cysts or those in thick-skinned/cosmetic areas 6.

Intraoral and Pressing Methods

• Intraoral Approach: For cysts near the lip or inside the cheek, removal through an incision inside the mouth avoids external scarring 9.
• Pressing Method: Involves making a tiny opening with a heated needle and squeezing out the contents and sac. Effective for small, noninfected cysts 10.

Electrosurgery

Some practitioners use electrosurgical methods to destroy the cyst sac with high-frequency electric current 10.

Aftercare and Recurrence

Complete removal of the cyst wall is crucial to prevent recurrence. If any part of the capsule remains, the cyst may reform 8 10. Infected cysts may require antibiotics before definitive removal.

When Is Removal Recommended?

• Cosmetic concern
• Recurrent infection or inflammation
• Rapid growth or suspicion of malignancy
• Discomfort or functional interference

Conclusion

Sebaceous cysts, while generally benign, can cause distress due to their appearance, discomfort, or risk of complications. Understanding the range of symptoms, the diversity of cyst types, causes, and the full spectrum of effective treatments equips patients and clinicians to make informed, patient-centered decisions.

Key Points:

• Sebaceous cysts usually appear as painless, movable lumps, but can become red, tender, or discharge material if infected or ruptured 2 3.
• Most "sebaceous cysts" are actually trichilemmal (pilar) cysts arising from hair follicles and filled with keratin, not true sebaceous material 1 2 3.
• Causes include keratin buildup, follicular blockage, genetic predisposition, and occasionally environmental or developmental factors 1 3 5.
• Treatment options range from minimal excision and punch biopsy to conventional or laser-assisted surgery, with choice depending on cyst characteristics and cosmetic concerns 6 7 8 9 10.
• Complete removal of the cyst wall is essential to prevent recurrence; special techniques may be used to minimize scarring, especially in visible areas 6 7 8 9.

If you notice a new skin lump or changes in an existing cyst, consult a healthcare provider for evaluation and to discuss the best treatment options for your needs.