Boils, Cysts, Ingrown Hairs, and 11 Other Skin Mysteries Explained

Updated: Apr. 23, 2024

Poof! A mysterious lump or bump appears on your body. What is it? How long has it been there? It's impossible to ask Dr. Google about a "lump on skin" and not lose your mind, but many times these lumps and bumps are nothing to lose sleep over.

Is it a keloid?

Trying to figure out what is causing the bumps on your skin can be hard. And really, the only way to know for sure is to consult a dermatologist, which we recommend. However, one potential cause is a keloid, which occurs when scar tissue grows excessively, explains Gary Goldenberg, MD, a dermatologist and an assistant clinical professor of dermatology at the Icahn School of Medicine at Mount Sinai Hospital in New York City. They often form around a wound or incision, but they may appear after a bad bout of acne. “Keloids are red, raised and can be itchy or painful,” he says. They’re more common in darker skin and often show up on the ears, chest, face or back. Many different treatments work alone or together to improve keloid scarring including steroid injections to flatten the scar, cryosurgery to freeze the scar tissue so it sloughs off, laser resurfacing, and surgery, he says. “You do need realistic expectations about how much keloid scarring can be improved with any treatment,” says Dr. Goldenberg. Learn about more surprising reasons you’re having skin problems.

close up of a skin tag

Is it a skin tag?

What are skin tags? Well, they are exactly what they sound like—tiny, soft skin-colored growths, Dr. Goldenberg says: “They often develop around the eyelids, armpits, groin or other areas that are easily rubbed or irritated.” Medically known as acrochordons, skin tags are more common if you are overweight, pregnant, or have diabetes. They are not harmful. “If they bother you, a doctor can freeze, laser, or snip them off,” he says. These are the myths about skin tags you need to stop believing.

close up of hives
Jana Kollarova/shutterstock

Is it a hive?

Do your bumps on skin itch like crazy? Tend to come and go? Get worse at night? If so, it could be a hive, Dr. Goldenberg says. Also known as urticaria, hives are usually a result of an allergy. Viruses can cause hives too, but many times you can’t pinpoint the cause of hives, which can be frustrating, he says. “If you know you break out in hives when you eat a certain food or are exposed to a specific chemical, avoid those triggers,” says Dr. Goldenberg. Over-the-counter antihistamines such as Benadryl or Zyrtec can also help curb the itching. An injectable, Xolair (omalizumab), is FDA-approved to treat chronic hives, and you can ask your doctor if it could help you.

close up of a wart on the palm of the hand
martin bowra/shutterstock

Is it a wart?

These are probably familiar, given how common they are. Warts are usually small skin-colored growths that feel rough when you touch them. Some may be sprinkled with tiny black dots. “They are caused by the human papillomavirus (HPV), and often occur on the hands and feet,” Dr. Goldenberg says. There are are over 100 types of HPV, and certain types can infect the reproductive tract, throat, anus, or genital area, and be sexually transmitted. Warts on your hands or feet can be tough to get rid of, but you can try over-the-counter solutions for warts, or opt for lasers or excision (where the doc cuts it out). Or try these natural remedies that can help get rid of warts on your face, hands, or feet.

close up of a cyst
Casa nayafana/shutterstock

Is it a cyst?

It’s alarming to feel or spot a cyst, but don’t hit the panic button. Cysts are harmless, closed pockets of tissue filled with fluid or other material. “They look and feel like balloon sacs under the skin,” says Dr. Goldenberg. They may disappear on their own, but some cysts may burst or cause symptoms such as pain or itching and require treatment. Whatever you do, “don’t try to squeeze them at home as this creates inflammation and will make things worse,” he warns.

man with very swollen lymph nodes
Karan Bunjean/shutterstock

Is it a swollen lymph node?

We have lymph nodes or bean-shaped organs all over our bodies. These super-important glands are tasked with recognizing and fighting germs, infections, and other intruders. If a swollen lymph node appears suddenly as a painful lump under the skin, it may be a sign of infection. Slow, painless swelling in the lymph node, however, may be more serious, though you’ll be happy to hear that only rarely are swollen lymph nodes caused by cancer, according to the Mayo Clinic. Better safe than sorry, though—if you are concerned about a swollen lymph node, see your doctor to find out what is going on. Learn some signs of disease that your skin can reveal.

keratosis on the upper arm

Is it keratosis pilaris?

KP is short for keratosis pilaris and is sometimes called chicken skin. KPs are small, hard and rough bumps on skin of the arms, legs or the butt. They are really just plugs of dead skin cells. “KP is associated with eczema, and doesn’t require treatment unless it is itchy or bothers you,” Dr. Goldenberg says. “Moisturizing with products that contain lactic acid, glycolic acid or salicylic acid can help exfoliate the bumps and smooth skin.” But, he warns, the minute you stop slathering on the cream, the KP will come right back. Learn more about chicken skin, and how to get rid of it.

elderly man's face with seborrheic keratosis

Is it seborrheic keratosis (SK)?

Seborrheic keratosis or SK is an extremely common colored skin growth. They may be beige, brown or even black. “SKs are non-cancerous, but they can look like skin cancer and sometimes may be sent to the lab to be sure,” Dr. Goldenberg says. Marked by multiple small, dark growths that tend to appear on the chest, back, head, or neck, according to the American Academy of Dermatology (AAD). If they bother you, SKs can be frozen, burned, scraped or shaved off, he says. Ask your dermatologist if they offer a specific topical drug called A-101, which can be applied in office, says Dr. Goldenberg. The lesion gradually and painlessly slough offs.

large lipoma on the forearm

Is it a lipoma?

Lipomas are harmless fatty tumors found under the skin. They feel soft and doughy and are often seen in the neck, shoulders, back, abdomen, arms, and thighs, according to the Mayo Clinic. “You can easily move them around, and they may be painful or quite large,” Dr. Goldenberg says. Radiologists can do a simple ultrasound imaging test to diagnose a lipoma. “Surgery, steroid injections and/or liposuction may be options, but no treatment is necessary unless you are bothered by it,” he says.

close up of a cherry angioma

Is it a cherry angioma?

If you have collections of bumps on the skin that are red you might have cherry angiomas, which tend to occur in people 30 or older. As the name suggests, these benign growths are bright cherry-red in color. “They are usually only treated for cosmetic reasons,” Dr. Goldenberg says. This is how you get rid of those cherry angiomas.

woman examining her breast

Is it a breast cyst?

Found a lump in your breast? Don’t panic: almost 80 percent of all breast lumps are noncancerous, according to Cleveland Clinic. According to Donnica L. Moore, MD, founder and president of Sapphire Women’s Health Group, located in the greater New York City area, “Breast lumps are extremely common, which is why it’s important to examine your breasts monthly and know what’s normal for you,” says Dr. Moore. Benign breast lumps are usually round with well-defined edges, freely movable, tender, and may change in size with hormonal ups and downs. If you notice a change in your breasts, tell your doctor. Here are some reasons (besides cancer) you could have a breast lump.

hematoma on a woman's upper arm

Is it a hematoma?

Ever notice a hard knot or lump in or around a recent bruise? “Don’t worry—this is probably a hematoma,” Dr. Moore says. “Hematomas are composed of a small amount of blood which has pooled into the fatty tissue under the skin,” she says. “While they often feel hard to touch, they may also feel spongy, rubbery or lumpy. They may be mobile, uncomfortable or painful,” she says. These lumps don’t typically require medical attention. “The blood will generally be reabsorbed as the bruise resolves,” she says, Icing the area and elevating it may help. ” Here’s how to identify 14 common skin rashes.

close up of a boil

Is it a boil?

A boil is a firm, painful lump that can look like an over-sized pimple. It’s usually caused by an infection of a hair follicle. “Boils may increase or decrease in size, or spontaneously drain, weep, or ooze,” Dr. Moore says. Applying warm compresses at home can help. In some cases, medical attention is required to lance or drain a boil. “People with cancer, diabetes or other causes of immunocompromised should seek medical attention whenever they develop this or any other skin infection,” she says. Here’s how to know the difference between a pimple and a boil.

close up of a suspicious mole

Is it skin cancer?

The sooner skin cancer is diagnosed, the easier it is to treat. The American Academy of Dermatology recommends regularly doing your own skin self-exam. For a handy how-to guide, follow these pointers from The Skin Cancer Foundation. Here’s how to recognize skin cancer if you see it.