Finding a lump under your skin can be surprising — and sometimes scary. This is true whether or not you live with hidradenitis suppurativa (HS). Most people can’t tell the difference between a boil and an abscess just by looking, but a few clues can help you tell them apart.

It’s important to meet with a dermatologist if you develop any new or painful skin changes. While you wait for your appointment, this guide can help you understand whether you may have an abscess or a boil — and what to do next.

What Are Abscesses?

An abscess is a pus-filled pocket that forms under your skin, in your mouth, or near your internal organs. On the skin, an abscess usually starts as a warm, tender nodule that may look discolored or swollen. Over time, the bump fills with pus. If the abscess bursts, pus — and sometimes blood — may leak out.

Abscesses can be the result of a bacterial infection (such as staphylococcus, also called a staph infection). Your body’s immune system sends white blood cells to attack the invading bacteria. This can cause nearby tissue to die, forming a pocket that fills with pus.

Some people develop abscesses as part of hidradenitis suppurativa. This chronic inflammatory condition causes painful lesions in areas where skin rubs together, such as the groin, buttocks, underarms, and under the breasts. These lesions can turn into abscesses that drain fluid, but they’re not the result of an infection.

Abscesses in the armpits, under the breasts, or near the buttocks can happen in both HS and skin infections, making the exact cause hard to figure out. That’s why it’s important to see a dermatologist or another healthcare professional if you have an abscess, especially if it keeps returning or doesn’t heal.

What Are Boils?

A boil is a painful, pus-filled lump under the skin. Boils (also called furuncles) form due to inflammation in a hair follicle. They may at first appear similar to abscesses, but boils affect only the top layer of the skin. Like abscesses, boils can be caused by bacterial infections such as staph.

Boils are usually smaller than abscesses, which also tend to be deeper under the skin. However, boils sometimes join together to form a carbuncle — a more painful infection that goes deeper and may look like an abscess. Both boils and abscesses may leak fluid when the skin breaks.

Abscess vs. Boil: Key Differences

Boils and abscesses have quite a few similarities, but they also have differences. Boils are typically small and shallow and tend to form around hair follicles. Most abscesses are quite deep under the skin.

How Do You Get Rid of an Abscess and Boil?

Some abscesses and boils heal on their own. If you need treatment, your dermatology provider or another healthcare professional will recommend the best option based on your skin condition. Below are some general guidelines.

How Are Abscesses Treated?

Minor abscesses may go away without treatment. Applying warm compresses can help the pus come to the surface and drain naturally. If the abscess doesn’t improve, a doctor may need to drain it in the office. They may also prescribe an antibiotic to clear the infection.

Don’t squeeze an abscess at home. This can spread bacteria to other parts of your body and make the infection worse.

How Are Boils Treated?

Boils usually heal in about two weeks. You can place moist, warm washcloths on the affected area a few times a day to help the boil drain. If the boil doesn’t go away, a doctor may need to drain it. This in-office procedure is called incision and drainage.

Your doctor might also recommend keeping the boil clean and covered, changing dressings (bandages) often. They may also prescribe topical or oral antibiotics.

As with abscesses, don’t try to cut or squeeze a boil. This can make it worse or spread bacteria.

How Is Hidradenitis Suppurativa Treated?

If your abscesses are due to hidradenitis suppurativa, your dermatologist will work with you to create a treatment plan. For mild HS, they may prescribe topical antibiotics. More severe cases might be treated with oral antibiotics, hormonal therapies, or biologics.

Surgery is sometimes used, but procedures recommended for HS tend to differ from the type used for abscesses caused by bacterial infections. For example, HS abscesses treated with incision and drainage return nearly 100 percent of the time. HS treatment usually includes a longer-term plan — combining medication, lifestyle changes, and possibly surgery tailored for HS.

When To Call a Doctor

Contact a dermatologist or another healthcare practitioner if you find a lump on your skin that doesn’t seem to be getting better. They can offer medical advice and treatment strategies.

When To See a Doctor About Abscesses

Get medical attention if your abscess:

• Becomes discolored or more swollen
• Gets more painful
• Is accompanied by a fever

When To See a Doctor About Boils

Reach out to your healthcare provider right away if a boil:

• Doesn’t improve with warm compresses after one week
• Keeps returning
• Forms on your face or the skin above your spine
• Becomes more painful
• Is accompanied by a fever

When To See a Doctor About Suspected Hidradenitis Suppurativa

If you notice abscesses, boils, or other lesions that keep coming back, you may have HS. A dermatologist can figure out if you’re experiencing HS symptoms, including painful lumps under the skin and lesions that rupture and leak discharge, which might smell.

HS often occurs in cycles, with flare-ups followed by periods when symptoms improve. A dermatologist can help diagnose HS and work with you to build a treatment plan that fits your needs.

Join the Conversation

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

Have you ever had to manage an abscess or a boil? Let others know in the comments below.