Whether you’ve been diagnosed with hidradenitis suppurativa (HS) or you’re curious about a new lump under your skin, learning the language to refer to your specific skin condition can help you better communicate with your dermatologist and track your symptoms over time.

Sometimes HS symptoms are called boils and cysts — but what exactly are boils and cysts? This article can serve as an educational guide, but be sure to see a dermatologist to make a diagnosis and find the treatment that is right for you.

1. Infections Lead to Boils, but Cysts Have Multiple Causes

Boils typically are caused by bacterial infections in the sebaceous glands surrounding hair follicles. A common type of bacteria that causes this infection is Staphylococcus aureus. The bacteria can enter the skin through a cut or break — for example, by a razor — and cause a staph infection.

Cysts are caused by the buildup of debris, such as fluid or keratin (the cells that make up skin and hair), in a sac beneath the skin. Many factors can trigger cysts to form, including blocked oil glands, trauma to skin, and genetic risk.

2. Boils May Look and Feel Like Infected Cysts

A boil is usually a swollen, discolored, painful bump filled with pus and often has a visible central core or head. It can be tender to the touch and range in size from that of a pea to a golf ball. A large boil is called an abscess.

One myHSteam member described having HS boils: “I am finding a repeating pattern of having boils that go large and firm and pus-filled and then go down and fill with blood. They don’t ever burst, but the skin is very thin and very painful.”

Cysts, however, appear as firm, round or dome-shaped lumps beneath the skin. They may or may not be painful and can be accompanied by discoloration or inflammation. A cyst that becomes inflamed or infected may turn into a boil.

3. Boils Occur in Sweat Glands, but Cysts Can Form Anywhere

Boils commonly affect areas with hair follicles and sweat glands. The highest density of these glands is in the face as well as in the armpits, groin, and buttocks — some of the most common areas where HS symptoms arise.

Cysts can occur anywhere on the body, including the face, neck, back, chest, and genitals. There are many types of cysts, and they affect different parts of the body. For example, similar to HS boils, sebaceous cysts occur in sebaceous glands. A mucocele is a fluid-filled cyst in a mucous membrane, such as the lips or vagina. “Who else mainly gets cysts in their inner labia?” one member asked.

4. Boils Need Care, but Cysts May Not

Boils may require topical or oral antibiotics to treat the bacterial infection and prevent it from recurring. Home remedies may include warm compresses to promote drainage and alleviate pain. If your boil doesn’t drain by itself with home treatment, it may be necessary to see a dermatologist for medical advice.

Some myHSteam members have described painful boils. “I have a track on my back that just burst yesterday — so much blood, pus, and pain. I really do hate these things. It’s still slowly draining,” one myHSteam member shared.

Another said, “’I’ve also had cortisone shots on four separate boils. They were extremely painful and hadn’t burst yet, so I had a shot in each, which did relieve the pain.”

A small, uninfected, painless cyst may not require treatment but can persist for years. A warm, moist compress can be used at home to relieve irritation or discomfort. If you have more serious or longer-term symptoms, a health care professional may decide to drain your cyst, inject corticosteroids, or surgically remove it. If you have signs of infection, such as pain, warmth, and discoloration, you might be prescribed antibiotics.

One member asked, “Do you all use topical lidocaine on cysts that haven’t opened up yet? Ibuprofen and the hot compress aren’t doing anything.”

If you are experiencing persistent symptoms, see your doctor about surgical or medical treatment. Try to avoid popping a cyst or boil at home, and see a dermatology professional to prevent complications.

5. Boils Are More Likely To Cause Complications if Untreated

Boils may resolve on their own but sometimes lead to serious complications if they aren’t treated. This could include abscess formation or the spread of infection to surrounding tissues (such as the brain, heart, or bone) or the bloodstream. A boil that heals improperly can cause permanent scarring, so it’s best to follow your dermatologist’s treatment and home care advice.

Cysts are usually benign, but if untreated, may become infected or cause symptoms. Rarely, they may rupture, leading to inflammation or secondary infections. “It took about two to three years for my cyst to fully drain because everything wasn’t taken out,” one member shared.

The healing process for boils and cysts looks different for everyone. It’s important to seek medical attention if you’re worried that your skin infection is getting worse or if you develop any systemic symptoms such as fever. Your health care provider will help you get the right treatment for boils, cysts, or any other HS symptoms you experience.

Talk With Others Who Understand

On myHSteam, the social network for people with hidradenitis suppurativa and their loved ones, more than 41,000 members come together to ask questions, give advice, and share their stories with others who understand life with hidradenitis suppurativa.

Do you experience boils, cysts, or both while living with HS? What advice do you have for others who are experiencing HS symptoms? Share your experience in the comments below, or start a conversation by posting on your Activities page.