Lump on the back under the skin

Back skin can develop cysts, blocked follicles, and other benign growths. A cyst may feel round and smooth, while an inflamed follicle or boil is often more tender, warm, and red. A deeper lump may feel mobile or firm, and its exact depth cannot be judged reliably from a mirror or photograph. A skin lump is a symptom rather than a diagnosis, so an examination may be needed.

Ask someone to help monitor a hard-to-see area for growth, crusting, bleeding, or a sore that does not heal. Those surface changes warrant review, including to consider uncommon conditions such as basal cell carcinoma; a back lump alone does not identify that condition.

Do not pierce, squeeze, or try to remove the lump yourself. Wash normally, avoid friction from tight straps or rough clothing, and note its position, approximate size, firmness, mobility, tenderness, and skin changes. A dated photograph can help show progression. Arrange a clinician appointment when the lump persists, returns, grows, catches on clothing, or limits movement. Depending on the examination, care may be observation, treatment for inflammation, drainage, removal, or a selected steroid injection into the skin.

Seek prompt medical care for rapidly increasing size, spreading redness, heat, severe pain, pus, fever, or chills. A lump that becomes fixed, breaks down, bleeds, or continues enlarging needs timely review. Sudden severe back pain with weakness, numbness, or loss of bladder or bowel control is an emergency and is not explained by an ordinary skin lump.

Ask whether the lump is within the skin or deeper, whether it resembles a cyst or inflamed follicle, whether imaging or removal is appropriate, and how to recognise a change that needs earlier care.