Boils and skin abscesses explained

What boils and abscesses are

A boil, also called a furuncle, starts when bacteria, usually Staphylococcus aureus, infect a hair follicle. The body sends white blood cells to fight the infection, and the resulting mixture of dead cells, bacteria, and fluid forms pus, creating a tender red lump that gradually comes to a head. A carbuncle is a cluster of connected boils, which tends to be larger and more painful. A skin abscess is a walled-off pocket of pus that can form in deeper tissue. Boils are more likely where skin rubs together or is exposed to sweat and friction, such as the neck, armpits, groin, buttocks, and thighs. Some people are more prone to them, including those with diabetes or a weakened immune system.

Recognising a boil

A boil usually begins as a firm, red, tender lump that grows over a few days as pus builds up. It often becomes softer and develops a yellow or white head at the centre, and may throb or feel warm. Many boils eventually burst on their own, releasing pus, after which the pain eases and the skin heals. A larger abscess feels like a swollen, tense, painful lump and may be accompanied by feeling generally unwell. Signs that the infection is spreading include increasing redness around the lump, red streaks running from it, swelling of nearby tissue, and fever. These features suggest the infection is no longer contained and needs medical assessment rather than continued home care.

Safe self-care

Most small boils can be managed at home while the body deals with the infection. Applying a warm, clean flannel or compress to the area for around ten minutes several times a day can ease pain and encourage the boil to come to a head and drain naturally. Keep the skin clean, and once a boil bursts, cover it with a clean, dry dressing and change it regularly to protect the area and stop the pus spreading. Wash your hands before and after touching it, and do not share towels or flannels, as boils are contagious through the pus. Simple pain relief from a pharmacy, taken as directed, helps with discomfort. A pharmacist can advise on suitable products and whether you need to see a GP.

Why you should not squeeze

It is tempting to squeeze or burst a boil to release the pus, but this is strongly discouraged. Squeezing can push the infection deeper into the skin and surrounding tissue, spread bacteria to new areas, worsen pain, and increase the risk of scarring. It can also introduce infection into the bloodstream in some cases. Instead, let the boil come to a head and drain on its own, helped by warm compresses. If a boil is large, very painful, not draining, or in an awkward or sensitive place, a clinician can drain it safely using a small procedure called incision and drainage, carried out under sterile conditions. This removes the pus properly and is far safer than attempting it yourself at home.

When to see a clinician and red flags

See a GP or seek medical advice if a boil is very large or extremely painful, is on the face, spine, or near the anus, does not improve or burst within about two weeks, or keeps coming back. Also seek help if you have several boils, or if you have diabetes or a weakened immune system, as infections can be more serious. Warning signs that need urgent attention include spreading redness, red streaks from the lump, significant swelling, a high temperature, or feeling generally very unwell, which can suggest the infection is spreading through the skin or body. If someone becomes rapidly unwell, confused, or develops signs of sepsis such as fast breathing or a racing heart, treat it as an emergency and phone 999.