Red lump under the breast: what to know

A lump in the fold can come from an inflamed hair follicle, blocked gland, cyst, moisture, friction, or local infection. A deeper lump may involve breast tissue. Redness, warmth, tenderness, drainage, or fever suggest inflammation, but appearance cannot confirm the cause.

A breast lump is a common presentation of breast cancer, but most breast lumps are not cancer. A new lump still needs examination. Tell the clinician how quickly it appeared and whether the breast, nipple, or armpit has changed.

Keep the area clean and dry, wear a breathable supportive bra, and avoid squeezing, puncturing, shaving over, or repeatedly pressing it. Note its size and edge without repeatedly touching it. Arrange an appointment for a new lump, especially if it remains after irritation settles.

A clinician may inspect and feel the area, then decide whether imaging or treatment is needed. Do not apply steroid, antibiotic, or herbal creams unless advised.

Seek same-day care if redness spreads, the area is hot and very painful, pus is present, or you have fever or feel unwell. Seek prompt assessment for a hard or fixed lump, skin dimpling, nipple inversion, bloody nipple discharge, or growth.

Ask whether the lump is in the skin fold or breast tissue, whether infection treatment is needed, and whether examination or imaging should follow. Explain its duration and any breast, nipple, or armpit changes.