Lump on tailbone under the skin: what to know

Pressure, sweating, and friction can make this area sore. A pilonidal-type problem may cause a tender swelling in the cleft, sometimes with drainage, but the position and examination are needed to distinguish it from other skin lumps.

Record whether the lump is in the cleft or to one side, whether the skin is red or warm, and whether fluid or blood appears. A boil can be painful and inflamed, while a cyst may recur after seeming to settle. A persistent crust, sore, or bleeding surface should also be examined; basal cell carcinoma can cause a changing skin lesion, although a tailbone lump has many other possible explanations.

Keep the area gently clean and dry, choose loose clothing, and avoid prolonged pressure where possible. Do not squeeze, pierce, or shave directly over an inflamed lump. Arrange a review if it is recurring, draining, enlarging, or making sitting difficult. Depending on the finding, care may include local treatment, drainage, removal, or a steroid injection into the skin for a suitable inflammatory lesion.

Contact a clinician promptly for increasing pain, spreading redness, warmth, pus, fever, or difficulty sitting or walking. Seek urgent care if you feel faint, become severely unwell, or have rapidly worsening swelling. A lump that bleeds, ulcerates, or changes steadily also needs timely assessment rather than repeated self-treatment.

Ask whether the swelling is in the skin or deeper tissue, whether drainage or imaging is needed, and how to reduce pressure on the area. Ask what recurrence would mean and which changes should bring you back sooner.