Lump Behind the Ear: Possible Causes Explained

A lump behind the ear can have many possible causes, such as swollen lymph nodes, infections, and skin conditions. These lumps are usually harmless and easy to treat, but you should keep an eye on a sudden lump or one that grows in size.

Less frequently, a non-cancerous (benign) or cancerous tumor can form behind the ear. In some cases, tumors may begin as small, soft spots but become large and harder as they grow.

This article discusses the common symptoms and possible causes of a lump behind the ear. It will help you to know when you should see a healthcare provider and what some of the treatment options are.

Causes of a Lump Behind the Ear

A lump behind the ear can form for several reasons. The most common causes of a lump in this spot are infections and skin conditions. In some cases, tumors can develop here.

A lump behind the ear can develop anywhere between the top of the ear down to the lobe. Depending in part on the cause, these small- to medium-sized bumps may feel soft or hard.

A lump might be tender or painful. Some lumps do not cause any discomfort.

Common Infections

You might notice a lump behind your ear when you get sick. There are lymph nodes behind the ear. Known as the posterior auricular lymph nodes, these can become swollen and inflamed if you catch strep throat or have an ear infection.

Other common infections can also cause swollen lymph nodes, such as:

• Abscessed or impacted teeth
• Gum disease
• Influenza or other upper respiratory infections
• Lyme disease (an illness caused by a bacterium carried by ticks)
• Mononucleosis (an infection caused by a herpes virus)
• Oral herpes (an infection of the herpes simplex virus)
• Sexually transmitted infections (STIs)
• Tonsillitis (inflammation of the tonsils in the back of the throat)

Serious Infections

German measles, also known as rubella, can cause these lymph nodes to swell.

In some cases, infected skin can lead to a growth called an abscess, which looks like a large pimple.

Mastoiditis, a bacterial infection affecting the mastoid bone behind the ear, can also cause a lump. This condition usually results from an untreated middle ear infection that spreads to the mastoid bone.

Other symptoms of mastoiditis include:

• Ear drainage
• Ear pain
• Fever
• Headache
• Redness around the ear
• Trouble hearing

Keloids

After getting your ears pierced, it's possible for a lump to appear behind the ear that doesn't go away. It's not common, but these lumps, called keloids, happen in about 2.5% of ear piercing cases.

Essentially, these are scars that grow beyond the site of a piercing or wound. They can be difficult to treat, as keloids have a tendency to grow back even after they're surgically removed.

Acne

Acne is a common skin condition that produces pimples, often due to hormonal changes. Acne can appear in many parts of the body, but the face is the most common site. Pimples can also develop behind the ears.

Over-the-counter (OTC) acne creams and face washes may help treat mild acne. More severe acne may require prescription-strength medication. A pimple can also become infected. Try not to scratch or touch pimples to reduce the chances of infection.

Lipomas

Lipomas are a type of skin growth. The fatty lumps of tissue are not hard and can be moved around under the skin. They can form in various parts of the body, including behind the ears.

Lipomas are harmless but can cause discomfort. You usually do not need to treat a lipoma unless it is bothering you. In this case, you can have it removed.

Cysts

Cysts are made up of dead skin cells and oils. They will feel soft to the touch and often go away on their own. 

Cysts are not usually painful unless they become infected. If this happens, antibiotics may be necessary. If a cyst causes discomfort or is likely to cause problems because of where it is located, it might need to be removed.

Eyeglass frames that don't fit well may irritate the skin and lead to cysts or other lumps. One type of nodule, called acanthoma fissuratum, can affect the nose and ears because of the persistent irritation. See your healthcare provider about these lumps in order to rule out skin cancer.

Benign or Malignant Tumors

A lump behind the ear can be a harmless (benign) tumor, as with a mastoid osteoma, or cancerous (malignant) tumor, as in cases of parotid (salivary) gland cancers.

It's not common for a lump behind the ear to be associated with lymphoma, and most lumps caused by nasopharyngeal cancers are found toward the back of the neck even though other ear symptoms may be involved.

But if you have a lump behind your ear and your healthcare provider wants to rule out cancer, they will usually need to perform a biopsy, a procedure that involves removing a sample of tissue to examine it more closely.

Bumps that are cancerous have several characteristics that make them different from harmless, more common lumps. Malignant lumps are more likely to:

• Be fixed in place
• Be uneven or irregular in shape
• Feel hard

When to See a Healthcare Provider

If you find a lump behind your ear, you might be wondering if you need to seek medical attention for it. While most lumps behind your ear are not serious, there are some cases for which you should have a healthcare provider take a look.

You should make an appointment if the lump behind your ear:

• Appears out of nowhere
• Is accompanied by other symptoms
• Is painful or causes discomfort 

Your healthcare provider will first do a simple examination. They will ask you questions about the lump—such as when you first noticed it—to figure out what is causing it.

Sometimes, the lump behind your ear will be a swollen lymph node. If this is the case, you should see a healthcare provider if:

• It is swollen, red, and painful.
• It feels hard like a marble.
• If it gets bigger or does not reduce in size after several weeks.
• You have other unexplained symptoms such as fever, night sweats, or weight loss.

If you have swollen lymph nodes with these other symptoms, your healthcare provider may wish to perform some blood tests, a biopsy, or a computed tomography (CT) scan to help make the correct diagnosis.

Treatment

Most infections that cause a lump behind the ear will go away on their own. For example, a mild ear infection that causes swollen lymph nodes may resolve on its own. However, bacterial infections will require antibiotic treatment. 

Some skin conditions that can cause lumps behind the ears are easily treated with OTC or prescription medications. Other skin lumps, like cysts or lipomas, might need to be removed.

In the case of tumors, treatment depends on whether the tumor is benign or malignant. In most cases, surgery will be required to remove the tumor. The bigger the tumor, the more complex the surgery will be.

Summary

A lump behind the ear can have several possible causes. Most of the time, the cause is something that is not serious and that will get better on its own or with minimal treatment.

However, if the lump hurts, gets bigger, or is accompanied by other symptoms, it should be checked out by a medical professional.

In rare cases, tumors can form behind the ear and require complex treatment. If you have a lump behind your ear and other symptoms, particularly if they show up suddenly, it's important to tell your healthcare provider. They can diagnose the cause and decide on the best course of treatment.