What should you know about pilar cyst contents?

A pilar cyst, also called a trichilemmal cyst, forms from a hair-follicle structure. Its lining produces keratin, a protein found in hair and skin, which gradually collects inside the capsule. The lump is often smooth, firm, and mobile under the scalp. It may have no visible opening. If the wall breaks, the material can spill into nearby tissue and trigger inflammation, making the area tender and swollen.

Do not squeeze, pierce, or try to drain a scalp cyst at home. This can injure the skin, introduce infection, and leave the capsule behind, allowing the lump to return. Avoid repeated friction from combs or tight headwear if it is sore. A clinician can examine the lump and discuss observation or removal; complete removal of the capsule is generally the part that helps prevent recurrence.

Arrange an assessment for a lump that is growing, repeatedly catching on a comb, painful, red, warm, draining, or associated with fever. Seek prompt care for rapidly increasing swelling or spreading redness. Any uncertain scalp lump deserves examination because not every lump has the same cause or contents.

Ask whether the lump has features of a pilar cyst, whether it is inflamed or infected, what removal involves, and how the scalp will be cared for afterward.