A lump behind your ear is almost always benign. The most common cause is a swollen lymph node triggered by a nearby infection like a cold, ear infection, or strep throat. Other possibilities include cysts, lipomas, abscesses, and keloid scars. Cancer behind the ear is uncommon, though not impossible. What the lump feels like, how fast it appeared, and whether you have other symptoms can help narrow down what you’re dealing with.
Swollen Lymph Nodes
There’s a cluster of lymph nodes just behind each ear called the posterior auricular nodes. These are part of your immune system, and their job is to filter out bacteria and viruses from the surrounding area, including your scalp, ears, and throat. When they’re fighting an infection, they swell up and become noticeable under the skin.
Common triggers include ear infections, strep throat, the common cold, mononucleosis, infected teeth, and skin infections like cellulitis. Even measles and certain sexually transmitted infections such as syphilis can cause lymph nodes in the head and neck to enlarge. Autoimmune conditions like lupus and rheumatoid arthritis occasionally do the same thing.
A swollen lymph node typically feels like a firm, pea-sized or marble-sized bump that’s tender when you press on it. It usually shows up on one side, close to wherever the infection is. If you’ve had a sore throat or stuffy nose recently, this is the most likely explanation. The node generally shrinks back to normal within two to three weeks once the underlying infection clears.
Cysts
Cysts are soft lumps made up of dead skin cells and oils that collect beneath the skin’s surface. The most common type behind the ear is an epidermoid cyst (sometimes called a sebaceous cyst). These tend to be round, slightly firm to the touch, and sometimes tender. They grow slowly, often over weeks or months, and they can range from the size of a pea to a couple of centimeters across.
Cysts are benign. Many people live with them without any problems. They can, however, become infected, at which point they turn red, warm, painful, and may start to drain. An infected cyst needs treatment, usually drainage and sometimes antibiotics. Even after removal, cysts occasionally come back.
Lipomas
A lipoma is a slow-growing lump of fatty tissue sitting just under the skin. If the lump behind your ear feels soft and doughy, moves easily when you press on it, and isn’t painful, a lipoma is a strong possibility. They’re harmless and don’t usually require treatment unless they’re bothersome or growing large enough to be cosmetically noticeable.
The key difference between a lipoma and a cyst: lipomas are softer and more mobile under your fingers, while cysts tend to feel firmer and more anchored in place. Lipomas are also almost never tender, whereas cysts often are.
Abscesses
An abscess forms when a skin infection causes a pocket of pus to collect under the skin. Behind the ear, these often look like large, swollen pimples. They’re usually red, warm, and painful. An abscess can develop from a minor scratch, an insect bite, or an infected hair follicle. Small ones may drain on their own, but larger abscesses typically need to be opened and drained by a healthcare provider.
Keloids From Piercings
If you’ve had an ear piercing, especially on the cartilage or upper ear, the lump could be a keloid. Keloids are raised, smooth scars that form when your body overproduces collagen during wound healing. They extend beyond the original piercing site and can appear weeks, months, or even years after the piercing. Keloids are benign but notoriously difficult to treat because they tend to return after surgical removal.
Mastoiditis
The mastoid bone is the hard, bony ridge you can feel directly behind your ear. It contains small air-filled pockets that connect to the middle ear. When a middle ear infection goes untreated or doesn’t fully resolve, bacteria can spread into these air cells and cause mastoiditis.
Mastoiditis feels different from the other causes on this list. Rather than a distinct movable lump, the entire area behind the ear becomes red, swollen, and extremely tender. The ear itself may be pushed forward or outward. Other symptoms include ear drainage, fever, and severe pain that worsens over time. This is a serious infection that can damage the bone if left untreated, so it requires prompt medical attention.
What the Lump Feels Like Matters
You can learn a lot by paying attention to a few characteristics:
- Soft, doughy, and painless: likely a lipoma.
- Firm, round, and slightly tender: likely a cyst or swollen lymph node.
- Pea-sized, appeared during or after an illness: almost certainly a lymph node.
- Red, warm, and painful with a visible “head”: likely an abscess.
- Hard, raised, and connected to a piercing site: likely a keloid.
- Widespread swelling with the ear pushed forward: possible mastoiditis.
Mobility is one of the most useful clues. Lumps that slide freely under your finger when pressed are generally benign. Lumps that feel fixed in place, rock-hard, or attached to deeper tissue deserve a closer look.
Signs That Need Attention
Most lumps behind the ear resolve on their own or turn out to be harmless. But certain features raise the level of concern. A lump that keeps growing over several weeks, doesn’t move when you press it, feels unusually hard, or is accompanied by unexplained weight loss, night sweats, or persistent fatigue should be evaluated. Parotid (salivary gland) cancers and lymphomas can occasionally present as lumps in this area, though tumors behind the ear are uncommon.
A lump that hasn’t shrunk after two to three weeks, especially if you don’t have an obvious infection to explain it, is worth getting checked. The same goes for any lump that’s rapidly increasing in size, causing numbness or weakness in your face, or is paired with severe ear pain and drainage, which could point to mastoiditis.
How Doctors Evaluate Ear Lumps
In most cases, a physical exam is enough. Your doctor will feel the lump, note its size and texture, check for tenderness, and look at the surrounding area for signs of infection. If the cause isn’t obvious, ultrasound is a common next step because it can distinguish between fluid-filled cysts, solid masses, and enlarged lymph nodes without any radiation. For lumps that look suspicious, a fine-needle aspiration (a quick procedure where a small sample of cells is drawn out with a thin needle) or a CT scan may be ordered to rule out anything serious.
For a straightforward swollen lymph node, no imaging is necessary. Your doctor will typically treat the underlying infection and confirm the node shrinks afterward. Cysts and lipomas that aren’t causing symptoms are often left alone and monitored over time.