If you’ve found a lump or bump under your skin, you may be concerned it’s something serious. The good news is that most lumps are harmless. Still, you should see a healthcare provider whenever you notice an unexplained growth or unusual swelling.
Bumps can pop up in all different places on your body. They can be benign (benign), malignant (cancerous), or infectious (caused by an infection). Normal, benign nodules are usually soft to the touch and roll easily under your fingers. They can cause pain if they become infected or inflamed. On the other hand, cancerous nodules usually grow in size and are hard, large, and painless.
This article discusses the most common types of skin lumps and when to worry about a potentially dangerous lesion.
13 possible types of nodules under the skin
There are many types of skin lumps and they can have different causes.
A cyst is a sac that can contain fluid, air, tissue, or some other material. It can form when the skin’s normal cell turnover is disrupted. Usually, cysts are not cancer.
You can identify a cyst by looking for a small opening called a pore or punctum in the center of the nodule. But sometimes this pore is hard to see. Cysts usually have a smooth surface and roll under the skin when pressure is applied.
There are hundreds of different types of cysts. Some common ones are:
- Epidermoid cysts: These contain skin cells and proteins.
- Sebaceous cysts: These are small sacs filled with keratin (a fibrous protein found in hair, nails and skin).
- Ganglion cysts: These appear on top of a joint or tendon and are caused by a buildup of leaking synovial fluid.
- Baker’s cysts: These are caused by a buildup of trapped synovial fluid behind the knee.
- Breast or ovarian cysts: These are usually benign.
lipomas are benign growths made up of fatty tissue. They are soft, small and rubbery nodules that sit just under the skin. Most lipomas appear on the shoulders, upper back, arms, buttocks, and thighs.
They usually don’t cause pain and can move if you press gently on them. Lipomas do not require treatment unless they cause discomfort or are unsightly.
Cause of lipomas
A dermatofibroma is a small, round, benign bump. They are usually pink, reddish or brown. Typically, dermatofibromas can be left alone, but surgery is an option for some people.
Swollen lymph nodes
If a lymph node is swollen, it can cause a bump under the skin. These nodules can be painful and hard to the touch.
Lymph nodes are bean-shaped organs in the lymphatic system. They house immune cells and serve to filter foreign particles from bodily fluids. They can enlarge and swell as part of the body’s response to a bacterial or viral infection. Less commonly, swelling of the lymph nodes can be a sign of cancer or another serious condition.
You may be able to feel lymph nodes in certain areas of your body, including the following:
- Under the chin and jaw
- Back of head
- Behind the ears
Moles are common skin growths that form when skin cells grow in a cluster. Most adults have 20 to 40 moles. They range in color from flesh-colored to dark brown. Moles are usually harmless, but some can be malignant. It’s a good idea to have a healthcare provider look at any suspicious mole.
Warts are benign growths on the skin caused by the human papillomavirus (HPV). They can grow anywhere, but are most common on the hands, fingers, and feet. There are different types of warts, including:
- Common warts: These are usually small, hard bumps that are dome-shaped and gray-brown in color. They have a rough surface that resembles a cauliflower, with black dots.
- Flat warts: These warts are smoother and have flat tops. They can be pink, light brown or yellow.
- Plantar warts: These usually form on the bottom of the foot and can be painful.
- filiform warts: These are shaped like a finger and are usually flesh colored.
Boils and abscesses
Cooks and abscesses are hard, painful nodules filled with pus (a collection of white blood cells, microbes, and tissue debris). They are usually caused by bacteria.
A boil is more superficial and can appear anywhere on the body, but usually affects the neck, face, armpits, buttocks, and thighs. An abscess may be deeper and the skin above it appears red, raised and swollen.
You may also be able to see yellow or white in the lump because of the pus that is under the surface of your skin. Some people also experience fever and chills with an abscess.
Often a boil or abscess will rupture and drain on its own. But sometimes a health care provider needs to step in and drain the pus.
A hernia occurs when a body part bulges through the muscle or tissue wall that normally holds it. Hernias may appear as a slight lump or bulge under the skin. They usually develop in the groin or abdomen and can cause pain.
A goiter is an enlarged thyroid — a gland in your neck that produces hormones to help control many functions in the body. A goiter appears as a swollen lump in the neck.
While usually harmless, some goiters are caused by thyroid cancer. For this reason, it is important to see a healthcare provider if you develop a goiter.
Fibroadenomas are benign breast tumors that usually:
When touched, fibroadenomas normally move easily. Sometimes no treatment is needed, but a surgeon can remove the benign growth.
Hemorrhoids are swollen veins in the anus and lower rectum. If you have a hemorrhoid, you may feel a bump or lump in these areas. You may also experience pain and swelling.
In rare cases, a lump under the skin may be cancerous. You may be able to feel cancerous growths under the skin in areas of the chest, testicles, neck, arms, or legs.
A type of skin cancer called soft tissue sarcoma can cause a cancerous growth almost anywhere on the body.
Testing a lump
When to Worry vs. Not to Worry
While it’s hard not to worry, you should know that most skin lumps are nothing to worry about.
Here are some signs that a suspicious lump may be harmful:
- It suddenly becomes very hard and feels like a stone under the skin.
- It’s growing fast.
- It starts to bleed.
- It’s going to be a wound.
It’s always a good idea to see a healthcare provider whenever you get an unexplained lump on your skin. They can help determine if it’s serious or harmless.
Screening and places to watch
Skin nodules can form almost anywhere on the body. It’s a good idea to perform regular self-examinations of your skin to look for new or unusual lesions. Many healthcare providers recommend a skin check once a month. For best results, skin exams should be performed in front of a mirror in a well-lit room.
Finding a lump under the skin is common and usually nothing to worry about. Lumps have different causes and can appear all over the body. Many benign nodules can be left alone without any treatment.
Rarely will a bump turn out to be cancer or another serious condition. Knowing the signs of a potentially dangerous growth can help you differentiate between a normal and an abnormal lesion.
Consult a healthcare provider about any new or suspicious-looking growth. If it is cancer, catching it early can increase your chances of successful treatment and a good outcome.
Frequently Asked Questions
Do cancerous nodules always hurt?
No. Cancerous nodules are often painless. However, in some cases they can cause discomfort.
What size nodules are considered abnormal?
Chunks can range from the size of a pea to larger than a golf ball. Lumps that are abnormal usually grow in size very quickly.
What is the difference between a cyst and a tumor?
A cyst is a sac that contains fluid, air, tissue, or some other type of material. On the other hand, a tumor is generally a solid mass of tissue.