What Can Cause a Pea-Sized Lump to Form in the Neck?

Causes of a pea-sized lump in the neck

A neck lump (also called a neck mass) has many potential causes. The following is a list of common reasons for a small, pea-sized neck lump to form.

Swollen lymph nodes

You have lymph nodes throughout your body, including pea-sized ones on both sides of your neck. Lymph nodes help filter out damaged or harmful cells from lymphatic fluid, and they also help fight infections by housing immune cells that fight disease.

Swollen lymph nodes in the neck can be a sign of a:

• viral infection
• bacterial infection
• tooth decay or abscess
• leukemia, a type of cancer

If a lymph node swells in response to an infection, it will usually shrink within two weeks. If the node remains unchanged or grows over a period of a few weeks, it could be something more serious, such as leukemia.

A lump swollen by leukemia is usually painless. If you are concerned about a lump on your neck, connect with a doctor.

Epidermoid cyst

An epidermoid cyst is located just under the skin’s surface and is filled with keratin, a protein that helps make up your skin and hair. These cysts are usually painless and are unlikely to cause problems. They can become inflamed, however, and may need to be removed.

Sebaceous cyst

Just under the skin are sebaceous glands that produce an oily substance (sebum) to keep your skin moisturized and protected. A sebaceous cyst can form if the gland’s duct becomes damaged or blocked and sebum builds up inside.

Muscle injury

An injured neck muscle may cause general swelling or a small lump to form under the skin. With rest, these injuries usually heal on their own.

Insect bite or sting

A raised and inflamed lump on the neck that appears suddenly may be a reaction to an encounter with a mosquito or other insect. Bug bites and stings tend to have a distinct look and may itch.

Cancer

In rare cases, a small lump that forms in the neck is a cancerous solid tumor or a swollen lymph node resulting from leukemia or lymphoma.

If the lump grows larger or does not shrink after two or more weeks, you should speak with a doctor.

Possible causes by location

You have hundreds of lymph nodes in your body, so a swollen node can occur almost anywhere. But in many cases, including the enlargement of certain lymph nodes, the location of the lump can help steer you and a doctor toward the right diagnosis.

Swollen lymph nodes in the neck can be a sign of a:

• viral infection, where the swollen nodes are typically the same on both sides of the neck
• bacterial infection, which usually affects nodes on one side of the neck, but may occur on both sides
• tooth decay or abscess, which would affect a node area on one side, just under the jawbone
• leukemia or lymphoma, though usually swollen lymph nodes due to this type of cancer also tend to occur in the groin or armpits rather than just the neck

What if the lump moves?

A softer lump that moves when you push it can be a healthy lymph node, a lipoma, or another harmless condition. A cancerous lymph node is usually hard and immovable, and some other cancerous masses may be harder as well. However, the size and location of the mass, as well as how long it has been visible, are all more important than how much or how little it moves.

Diagnosing the cause

A doctor will examine the lump during a physical examination to evaluate the cause of a mass forming in the neck. They may also check for swelling in other lymph nodes in the body, particularly the armpits and groin.

You should also be prepared to provide your medical history, any family history of diseases like cancer, and a description and timeline of your symptoms. A doctor will likely order a complete blood count (CBC) and other specific blood work to test for markers of illness, such as:

• blood glucose (sugar) level
• protein levels
• thyroid function testing
• electrolyte levels

Lymph nodes that have remained swollen or continue to grow larger may be biopsied to determine whether the cause is a chronic infection, autoimmune condition, or cancer.

Imaging, including a neck X-ray, a computed tomography (CT) scan, or ultrasound may also be ordered.

Treating the underlying cause

A lump in the neck is usually temporary and harmless, but in rare cases, it can be a more serious problem. Treating the underlying cause of the neck mass will typically cause the lump to recede. In some cases, though, the lump itself can be removed, as there is no other underlying cause to treat.

Viral infections

If the lump has occurred due to a common viral infection, then rest and fluids are the typical treatment. For serious infections, antiviral medications may be needed.

Bacterial infection

A course of antibiotic treatment may be necessary. And depending on the nature of the infection, other treatments could be required, too. For example, a respiratory infection may mean you need an inhaler to help open the airways in the lungs.

Sebaceous cyst

A cyst may be drained of fluid, but in many cases they are surgically removed for cosmetic reasons.

Muscle injury

Rest and ice should bring down the inflammation and swelling. Once your muscle has healed, massage may help you keep the muscle more relaxed and less likely to tense and become injured.

Cancer

Whether it’s leukemia, lymphoma, or another type of cancer, treatment will depend on the severity of the disease. The stage and grade of the cancer will determine whether radiation therapy, chemotherapy, surgery, or some other treatment is the best approach.

Takeaway

A pea-sized lump in the neck is most likely a swollen lymph node and a sign your body is fighting an infection or an allergic reaction. If the lump, also known as a mass, retreats within a week or so and you have no other symptoms, then no medical attention is required.

If, however, the lump grows or becomes painful, or if you are experiencing symptoms like fever, difficulty swallowing, fatigue, or other signs of illness, then you should speak with a doctor immediately.