Hard Lump on Tailbone Under Skin: What to Know

The tailbone region is exposed to pressure, friction, sweat, and trapped hairs. A lump in the crease may become sore when sitting, while an uninfected cyst or other growth may be firm without much surface change. Record whether it is centered in the crease, whether fluid or blood appears, and whether discomfort follows sitting. A location-specific description helps a clinician assess [Skin Lumps](/symptoms/skin-lumps/) without assuming the cause.

Keep the crease gently clean and dry, wear breathable clothing, and reduce direct pressure if sitting aggravates it. Avoid squeezing, digging for a hair, or applying harsh products. Book an appointment if the lump remains, becomes recurrent, or makes sitting difficult. Depending on the findings, care may involve observation, drainage, removal, or another treatment; a steroid injection into the skin is suitable only for selected problems.

Seek prompt care for increasing warmth, spreading redness, worsening pain, pus, bleeding, fever, or difficulty sitting and moving. A persistent sore or crusted lump also deserves examination, particularly if it changes rather than settling. These findings can occur with [Boils](/conditions/boils/) and other conditions; [Basal Cell Carcinoma](/conditions/basal-cell-carcinoma/) is another diagnosis a clinician may consider when a lesion has concerning surface changes.

Ask whether the lump is in the skin or deeper in the crease, whether infection is present, and whether it could be a cyst. Ask how to protect the area while sitting, whether a procedure is needed, and which symptoms should trigger an earlier review.