What Causes a Lump on Your Arm?

It’s not uncommon to find a lump on your arm under the skin. Most people will develop a lump of some kind in their lifetime. Many of the causes of these lumps are harmless or benign. Read on to learn more about the causes of a lump on your arm. This article also discusses how they are treated and when to contact a doctor.

A lipoma is a noncancerous tumor that is made up of fatty tissue. These lumps are typically located just under the skin and tend to be soft and rubbery.

Lipomas are typically painless and commonly found in the following areas:

• arms
• upper back
• shoulders
• buttocks
• upper thighs

Lipomas can occur at any age but are most common in people aged 40–60.

Lipomas typically do not change, and there is little risk of them becoming cancerous. Treatment for a lipoma usually involves observation. However, if they become painful or grow larger, your doctor may recommend surgical removal.

Read more about lipomas.

An abscess is a collection of pus that is typically due to a bacterial infection. Skin abscesses tend to be painful, swollen lumps that form just beneath the skin. They can appear anywhere on the body.

An abscess may also be accompanied by symptoms of infection, such as a fever and chills. Contact your doctor if you believe you may have an abscess.

Smaller abscesses may drain naturally. They may also shrink, dry up, and disappear on their own. Larger abscesses may require treatment with antibiotics. Your doctor may need to drain the pus from them as well.

Read more about abscesses.

Cysts are fluid-filled lumps under the skin. They are typically harmless and disappear on their own without treatment.

Epidermoid cysts often appear on areas of the body with little hair. This can be anywhere on the body, but may include:

• arms
• neck
• trunk
• face

Epidermoid cysts range from skin-toned to yellow in color. They are generally firm, round nodules and typically appear in adults.

Ganglion cysts are most commonly found on the joint of the wrist, though they can appear in a variety of locations. They grow out of the tissue surrounding a joint.

Cysts often disappear on their own and may not require treatment. However, large, painful cysts may require aspiration or draining of the fluid, or surgical removal.

Read more about cysts.

Dermatofibromas are small, hard lumps under the skin. They most commonly appear on the lower legs, but can occur anywhere on the body. They typically affect exposed areas and can range in color from brownish to reddish-purple.

Dermatofibromas are usually harmless and noncancerous and mainly occur in adults. They generally do not cause any other symptoms, but can be tender or itchy.

Dermatofibromas typically do not require treatment. If they become a nuisance or cause for concern, you may wish to have them removed. Removal involves shaving the top of the lump and punching out the center, or freezing it with liquid nitrogen. It should be noted, though, that these treatments are rarely successful.

Basal cell carcinoma is the most common type of skin cancer, according to the American Cancer Society (ACS). They account for approximately 8 out of 10 Trusted Source American Cancer Society Highly respected international organization Go to source cases of skin cancer.

This type of cancer typically occurs in areas of the body exposed to UV radiation from the sun. Early signs of basal cell carcinoma include:

• shiny bumps
• open sores
• red or discolored patches
• growths with a slightly raised edge

It is important to get treatment for basal cell carcinoma as early as possible. Treatment options include:

• surgery
• cryotherapy
• light therapy
• topical medication

Read more about basal cell carcinoma.

Melanoma is a type of skin cancer. While not as common as other skin cancers, it is more serious Trusted Source American Cancer Society Highly respected international organization Go to source . This is because it is more likely to spread to other areas of the body.

The most common signs of melanoma are:

• unusual moles
• sores
• lumps
• markings
• changes to the way your skin looks or feels

Read more about other symptoms of melanoma.

Treatment for melanoma can depend on the stage of the cancer and your overall health. Talk with your doctor about your treatment options.

Treatment options for melanoma include:

• surgery
• immunotherapy
• targeted therapy
• chemotherapy
• radiation therapy

Read more about melanoma.

Other causes of lumps on your arm can include:

• warts
• insect bites
• trauma or injury
• benign growths

Contact your doctor if you have a new lump on your arm that is not due to an insect bite or injury. While usually not a cause for concern, it may require testing or treatment.

It is important to have your doctor regularly check for changes to your skin. They may be able to identify lumps early and recommend treatment as soon as possible.

There are several possible causes for a lump on your arm, many of which are noncancerous. In some cases, a new spot, bump, or lump on your skin may be a sign of skin cancer.

Lumps like cysts and lipomas typically do not require treatment. However, it is important to contact your doctor for a diagnosis. This can help rule out more serious causes such as skin cancer.

Lumps that are cancerous require treatment. Seeking treatment early will increase your chance of success and recovery. Contact your doctor if you are concerned about any new lumps, bumps, or changes to your skin.