An abscess is a buildup of pus and is a sign that your immune system is trying to fight off an infection. Pus is a thick white or yellow fluid made up of white blood cells, dead tissue, germs, and other fluids from your body.

Abscesses can form on your skin or inside your body. Some types of abscesses are more serious than others. Here’s why they happen and what you can do about them.

Why Do Abscesses Form?

White blood cells — also called leukocytes — protect the body from illness-causing threats like viruses and bacteria. White blood cells rise when the immune system kicks into gear. Inflammation or stress in the body can also lead to more white blood cells.

Abscesses usually form when the body has a strong immune response, often due to a bacterial infection. The resulting inflammation creates a pocket under the skin or in the body. This pocket fills with pus as the immune system works to contain the infection.

Sometimes an abscess forms because of an inflammatory medical condition, not an infection. For example, hidradenitis suppurativa (HS) is a long-term skin disease that causes repeated abscesses.

In people with HS, the immune system overreacts and causes inflammation around hair follicles. This leads to painful symptoms like abscesses and boils (smaller pus-filled bumps) that typically affect skin folds, such as the armpits, groin, and buttocks. HS is more common in women and Black people, especially those with a family history of the condition, according to the HS Foundation.

Should You See a Doctor?

Abscesses may make the affected area swollen, tender, and warm to the touch. An underlying infection can also cause fever and chills. If you think you have an abscess, contact your healthcare provider. Depending on where the abscess is located and how severe it is, they may recommend an in-office procedure called incision and drainage or prescribe antibiotics to promote healing. For a small abscess, applying a warm compress at home might be enough.

Signs of a worsening infection should be addressed right away. If the area gets more swollen and painful, follow up with your healthcare provider.

Why Do Abscesses Keep Coming Back?

If your skin problems keep returning, it’s important to see a dermatologist. You may have a chronic skin condition like HS that needs more than a one-time treatment. A dermatologist can help diagnose the cause and recommend treatment to manage HS symptoms and prevent flare-ups.

HS can be hard to identify, but one common sign is abscesses or other symptoms that happen at least twice within six months. Without treatment, larger abscesses can lead to more serious issues, including infections, scars, or tunnels that form under the skin.

Some people with HS end up in the emergency department before learning what’s really causing their symptoms. Being proactive by seeking medical attention early can help you get the right care and avoid more serious problems.

Talk With Others Who Understand

On myHSteam, people share their experiences with hidradenitis suppurativa, get advice, and find support from others who understand.

Do you have skin infections that don’t seem to go away for long? Do you think your skin abscesses could be a sign of HS? Share your experience in the comments below.