Overview
The term "sebaceous cyst" is commonly used to describe several types of cysts that occur in the skin, though technically most are epidermoid or pilar cysts. These benign growths develop when the opening of a hair follicle becomes blocked or when trauma damages a hair follicle. The cyst forms as a sac beneath the skin that fills with a thick, cheese-like substance composed primarily of keratin, the protein that makes up hair and skin cells.
These cysts are extremely common, affecting people of all ages, though they rarely appear before puberty. They grow slowly over months or years and typically remain small, ranging from a few millimeters to several centimeters in diameter. While generally harmless, they can become inflamed, infected, or cosmetically bothersome, prompting many people to seek treatment. The cysts are not contagious and do not increase cancer risk, though any rapidly growing or changing skin lesion should be evaluated by a healthcare provider.
Understanding the nature of these cysts helps alleviate concerns and guides appropriate management. Most sebaceous cysts require no treatment unless they become symptomatic or are located in areas where they interfere with daily activities. When treatment is desired, several options are available, from simple drainage to complete surgical excision. The choice depends on the cyst's size, location, symptoms, and the patient's preferences.
Symptoms
Sebaceous cysts typically present as slow-growing, painless bumps beneath the skin. While usually asymptomatic, they can develop various characteristics that help identify them and determine if treatment is needed.
Common Symptoms
- Skin swelling - Dome-shaped bump beneath the skin surface
- Abnormal appearing skin - Visible changes in skin texture or appearance over the cyst
- Skin lesion - Distinct area of altered skin
- Acne or pimples - May be mistaken for or occur alongside cysts
- Skin growth - Palpable mass that moves with the skin
- Irregular appearing scalp - Common location for pilar cysts
- Neck mass - Frequent site for cyst development
- Skin moles - May occur near cysts or be confused with them
- Hand or finger lump or mass - Less common but possible location
- Back mass or lump - Common site, especially upper back
- Arm lump or mass - Can occur anywhere on extremities
Characteristic Features
- Round or dome-shaped bump - Smooth, well-defined borders
- Mobile under the skin - Moves freely when touched
- Central punctum - Small dark spot or opening (not always present)
- Firm or fluctuant texture - May feel solid or slightly fluid-filled
- Skin-colored or yellowish - Usually matches surrounding skin tone
- Size variation - From pea-sized to several centimeters
Symptoms of Complications
- Inflammation - Redness, warmth, and tenderness
- Infection - Pain, swelling, pus discharge, fever
- Rupture - Discharge of thick, foul-smelling material
- Rapid growth - Sudden size increase may indicate inflammation
- Discomfort - From pressure on surrounding structures
Causes
Sebaceous cysts develop through various mechanisms that lead to the accumulation of keratin or other materials beneath the skin. Understanding these causes helps in prevention and management.
Primary Causes
- Blocked hair follicles - Most common cause of epidermoid cysts
- Damaged sebaceous glands - From trauma or inflammation
- Developmental defects - Embryonic cells trapped during development
- Skin trauma - Injury pushing surface cells deeper into skin
- Surgical implantation - Cells displaced during procedures
Types and Their Specific Causes
Epidermoid Cysts:
- Blocked hair follicle opening
- Skin trauma or injury
- Acne or skin conditions
- Sun damage to skin
Pilar Cysts (Trichilemmal Cysts):
- Genetic predisposition (autosomal dominant)
- Hair follicle damage
- More common on scalp
- Often multiple cysts in families
True Sebaceous Cysts:
- Blocked sebaceous gland duct
- Sebaceous gland damage
- Rare compared to epidermoid cysts
- Associated with steatocystoma multiplex
Contributing Factors
- Hormonal changes - Puberty, pregnancy influence sebum production
- Genetic syndromes - Gardner syndrome, Gorlin syndrome
- Chronic skin conditions - Acne, folliculitis
- Poor hygiene - May contribute to follicle blockage
- Excessive sun exposure - Skin damage and changes
Risk Factors
While sebaceous cysts can affect anyone, certain factors increase the likelihood of developing these benign skin growths.
Demographic Factors
- Age - Rare before puberty, most common in adults 20-60 years
- Gender - Slightly more common in males
- Genetics - Family history, especially for pilar cysts
- Ethnicity - No significant racial predisposition
Medical History
- Previous cysts - Higher risk of developing more
- Acne history - Damaged follicles prone to cyst formation
- Skin injuries - Trauma increases risk at injury site
- Previous skin surgery - Scar tissue may trap cells
Genetic Conditions
- Gardner syndrome - Multiple epidermoid cysts
- Gorlin syndrome - Basal cell nevus syndrome
- Steatocystoma multiplex - Multiple sebaceous cysts
- Familial cylindromatosis - Multiple scalp tumors
Environmental Factors
- Sun damage - Chronic UV exposure
- Occupational exposure - Oils, chemicals affecting skin
- Poor skin care - Inadequate cleansing
- Repeated friction - Areas of chronic rubbing
Other Risk Factors
- Hormonal fluctuations - Puberty, pregnancy, menopause
- Immunosuppression - May affect cyst development
- Obesity - Skin fold friction and moisture
- Certain medications - Drugs affecting skin cell turnover
Diagnosis
Diagnosis of sebaceous cysts is typically straightforward and based on clinical examination. However, additional tests may be needed to confirm the diagnosis or rule out other conditions.
Clinical Evaluation
- Visual inspection - Characteristic appearance and location
- Palpation - Feeling the cyst's texture and mobility
- Size measurement - Document dimensions for monitoring
- Central punctum - Look for characteristic opening
- Skin examination - Check for multiple cysts or other lesions
Patient History
- Duration - How long the cyst has been present
- Growth rate - Speed of enlargement
- Symptoms - Pain, discharge, previous infections
- Previous cysts - History of similar lesions
- Family history - Genetic predisposition
- Trauma history - Injury to the area
Diagnostic Tests
When Additional Testing is Needed:
- Atypical appearance
- Rapid growth
- Deep or fixed lesions
- Multiple cysts
- Diagnostic uncertainty
Available Tests:
- Ultrasound - Shows cyst structure and contents
- Fine needle aspiration - Sample cyst contents
- Biopsy - If malignancy suspected
- CT or MRI - For deep or complex cysts
- Histopathology - Definitive diagnosis after removal
Differential Diagnosis
Conditions that may mimic sebaceous cysts:
- Lipoma - Deeper, softer, no central punctum
- Abscess - Painful, red, warm, fluctuant
- Dermoid cyst - Present at birth, midline location
- Ganglion cyst - Near joints or tendons
- Pilomatrixoma - Hard, calcified, in children
- Basal cell carcinoma - Pearly, telangiectasias
Treatment Options
Treatment for sebaceous cysts depends on their size, location, symptoms, and patient preference. Many cysts require no treatment unless they become bothersome or infected.
Conservative Management
- Watchful waiting - Monitor asymptomatic cysts
- Warm compresses - May help small cysts drain naturally
- Avoid squeezing - Prevents infection and scarring
- Keep area clean - Gentle cleansing to prevent infection
Medical Treatments
For Inflamed Cysts:
- Intralesional steroids - Reduces inflammation
- Oral antibiotics - If secondary infection present
- Topical antibiotics - For minor infections
- Anti-inflammatory medications - Reduces swelling and pain
Surgical Options
Incision and Drainage:
- Quick relief for infected cysts
- Local anesthesia
- High recurrence rate
- May need packing changes
- Not definitive treatment
Complete Excision:
- Gold standard treatment
- Removes entire cyst wall
- Low recurrence rate
- Performed under local anesthesia
- Small scar results
Minimal Excision Technique:
- Smaller incision
- Cyst contents expressed
- Wall removed through small opening
- Less scarring
- Good cosmetic results
Other Procedures
- Laser therapy - CO2 laser for cyst wall destruction
- Punch biopsy excision - For small cysts
- Electrocautery - After drainage to destroy wall
Post-Treatment Care
- Wound care - Keep incision clean and dry
- Dressing changes - As directed by physician
- Activity restrictions - Avoid strenuous activity initially
- Follow-up visits - Monitor healing and remove sutures
- Scar management - Silicone sheets, sun protection
Prevention
While not all sebaceous cysts can be prevented, certain measures may reduce the risk of developing them or prevent existing cysts from becoming problematic.
Skin Care Practices
- Regular cleansing - Keep skin clean to prevent follicle blockage
- Gentle exfoliation - Remove dead skin cells
- Avoid harsh products - Prevent skin irritation
- Non-comedogenic products - Won't clog pores
- Proper makeup removal - Thorough cleansing at night
Lifestyle Modifications
- Avoid picking or squeezing - Prevents trauma and infection
- Protect from sun damage - Use sunscreen regularly
- Manage acne properly - Reduce follicle damage
- Treat skin injuries promptly - Clean and protect wounds
- Avoid tight clothing - Reduce friction in prone areas
Medical Prevention
- Early treatment - Address cysts before complications
- Genetic counseling - For familial cyst syndromes
- Regular skin checks - Monitor for new growths
- Manage underlying conditions - Treat acne, skin disorders
Post-Treatment Prevention
- Complete removal - Ensure entire cyst wall excised
- Proper wound care - Prevent infection and scarring
- Follow-up care - Monitor for recurrence
- Scar prevention - Appropriate wound management
When to See a Doctor
While sebaceous cysts are generally harmless, certain situations warrant medical evaluation to rule out other conditions or address complications.
Seek Immediate Medical Attention If:
- Rapidly growing mass (days to weeks)
- Signs of severe infection (high fever, spreading redness)
- Severe pain or tenderness
- Red streaks extending from the cyst
- Facial cysts with vision changes
- Multiple cysts appearing suddenly
Schedule an Appointment For:
- Cyst that interferes with daily activities
- Cosmetic concerns
- Recurrent infections
- Discharge or bleeding from cyst
- Change in cyst appearance
- New cyst in person over 40
- Multiple family members with cysts
Signs of Complications
- Infection - Increased pain, redness, warmth, pus
- Rupture - Sudden drainage, inflammation
- Abscess formation - Fluctuant, painful swelling
- Cellulitis - Spreading skin infection
- Scarring - From repeated inflammation
When Removal is Recommended
- Recurrent infections
- Functional impairment
- Diagnostic uncertainty
- Patient preference for cosmetic reasons
- Cysts in areas prone to trauma
- Large cysts (>5 cm)
References
- Zubair M, et al. (2023). Sebaceous Cysts: A Comprehensive Review of Pathogenesis, Diagnosis, and Treatment. Dermatologic Surgery.
- American Academy of Dermatology. (2023). Sebaceous Cysts: Diagnosis and Treatment Guidelines.
- Higgins JC, et al. (2023). Epidermoid and Pilar Cysts: A Review. Journal of Clinical and Aesthetic Dermatology.
- Lee JY, et al. (2022). Minimal Excision Techniques for Epidermal Cysts. Archives of Dermatology.
- British Association of Dermatologists. (2023). Patient Information Leaflet: Epidermoid and Pilar Cysts.