Sebaceous Cyst in the Mouth: What to Know

The term sebaceous cyst is often used for an epidermoid cyst, a sac containing keratin rather than a true cyst from a sebaceous gland. These cysts are more typical in skin than on moist tissue inside the mouth. A bump may instead be a blocked minor salivary gland, a mucocele, irritation from biting, an infection, or another oral lesion. A clinician may inspect the surface, feel the area, and ask when it appeared and whether it changes.

A lump that is soft, firm, clear, white, red, or tender cannot be identified reliably from appearance alone. Do not squeeze it or pierce it, since this can cause bleeding, infection, or more inflammation.

Arrange an assessment with a dentist, oral health clinician, or doctor, especially if the lump persists. Keep the area clean, avoid biting or rubbing it, and choose foods that do not irritate a sore spot. Note changes in size, colour, drainage, tenderness, or position. Depending on the finding, care may involve observation, treatment of inflammation, drainage of an abscess, or removal of a cyst. Read about [Skin Lumps](/symptoms/skin-lumps/) and [Cyst Removal](/treatments/surgical-dermatology/cyst-removal/) for context.

Seek prompt medical or dental care if swelling is rapidly increasing, pain is severe, pus or foul-tasting fluid appears, fever develops, or the area makes swallowing, speaking, breathing, or opening the mouth difficult. Bleeding that does not settle also needs assessment. Urgent symptoms are driven by what the lump is doing, not by the label sebaceous cyst.

Ask: Could this be a salivary-gland cyst or irritation rather than an epidermoid cyst? Does it need examination by a dentist or oral specialist? If it is infected, would [Abscess Drainage](/treatments/minor-procedures/abscess-drainage/) be appropriate? Would an [Intralesional Steroid Injection](/treatments/injectables/intralesional-steroid-injection/) have a role, or would that be unsuitable for this location?