Infected cyst under the skin: what to know

A skin cyst is a closed sac beneath the surface. Inflammation or infection may cause tenderness, heat, redness, swelling, a visible opening, or thick fluid. These changes can resemble an abscess or another skin lump, so examination helps determine the safest next step.

The skin may look calmer after fluid escapes while the cyst lining remains. That is why a lump can return after temporary improvement. A clinician may discuss observation, an injection for selected inflammation, drainage when pus has collected, or removal once active inflammation has settled.

Keep the area clean, avoid pressure and friction, and use a clean warm compress briefly if it is soothing. Wash hands before and after touching the lump. Never squeeze, lance, or dig into it, and avoid applying strong antiseptics or unprescribed antibiotics. If it opens, cover it with a clean dressing and arrange advice about ongoing care.

Arrange prompt assessment for increasing pain, spreading redness, pus, rapid enlargement, or a lump that interferes with movement or sleep. Seek urgent care for fever, chills, faintness, rapidly spreading swelling, severe pain, or redness close to the eye. A recurrent, firm, fixed, or changing lump also deserves an examination even when it is not sore.

Ask whether this is a cyst, abscess, or another lump; whether drainage is appropriate; how to dress the area; and whether an injection or later cyst removal could help prevent recurrence. Ask what change should prompt same-day review.