Redness around a boil that is spreading

A boil is a tender, pus-filled infection centred on a hair follicle. When warmth, swelling, or redness moves beyond the original lump, the surrounding skin may be involved. [Cellulitis](/conditions/cellulitis/) is one condition that presents with expanding redness, warmth, tenderness, and swelling; the redness itself does not establish the diagnosis. A deeper pocket of pus may also need assessment. Mark the edge lightly and note the time so you can describe whether it is advancing. Do not squeeze, pierce, or cut the boil, because this can push infection into nearby tissue or spread it to others.

Arrange same-day clinical advice when redness is expanding. Keep the area clean, cover any drainage with a fresh dressing, wash your hands after touching it, and do not share towels or razors. A clinician may decide whether drainage, a swab, or [Antibiotics For Skin Infection](/treatments/medical-dermatology/antibiotic-therapy-for-skin-infection/) is suitable. Take prescribed medicine exactly as directed and do not use leftover antibiotics.

Get urgent help for fever, chills, feeling faint or confused, rapidly increasing pain, red streaks, facial or eye involvement, or a boil near the nose or spine. People with diabetes, immune suppression, or poor circulation should seek advice promptly even if the area seems small.

Could this be cellulitis or a deeper abscess? Does it need drainage or a swab? Which warning signs should make me return urgently, and how should I protect household members?