Benign cyst on the scalp: what to know

An examination is still worthwhile when the diagnosis is uncertain, because several types of skin lump can occur on the scalp.

A pilar, or trichilemmal, cyst forms from the outer root sheath of a hair follicle and contains keratin. It commonly feels round, mobile and firm beneath otherwise normal skin. More than one can occur, and similar cysts may run in families.

A cyst may remain quiet for a long time, enlarge gradually or become sore after pressure or inflammation. If it ruptures, keratin can trigger marked redness and tenderness even without a bacterial infection.

Leave a comfortable, clinically diagnosed cyst alone unless monitoring or removal is recommended. Avoid squeezing, puncturing or repeatedly pressing it; this can inflame the area and makes infection more likely.

Removal may be considered when the lump catches during hair care, hurts, repeatedly inflames, grows or causes concern. The clinician aims to remove the cyst wall as well as its contents, because leaving the wall can allow the lump to return. Inflamed cysts may need the inflammation managed before planned removal.

Seek prompt medical assessment if the lump grows quickly, becomes very painful, feels hot, drains pus, bleeds without injury or is accompanied by fever. A hard fixed lump, an open sore or a lesion that returns after removal also deserves reassessment.

Urgency comes from these changes, not from the mere presence of a scalp lump. A clinician can decide whether examination is enough or whether imaging, removal or pathology testing is appropriate.

Ask which type of lump is suspected, what alternatives were considered, whether observation is reasonable, how removal would affect the surrounding hair and what wound care would involve. If tissue is removed, ask whether it will be sent for pathology examination.