In most cases, hard lumps found behind the ear don't cause any symptoms. They are usually harmless if they are not associated with any pain, itchiness, or discomfort. Many times, they can just be a result of acne or a benign cyst.
However, lumps can also appear due to infections in the area, requiring more attention and appropriate treatment. Therefore, if the lump causes pain, takes a long time to resolve, is very irregular in shape or if it increases in size, a consult with your doctor or a dermatologist is recommended for diagnosis and treatment as indicated.
There are many causes for hard lumps found behind the ear. These include:
Lumps behind the ear can be caused by throat infections (e.g. pharyngitis), a cold or flu virus, mononucleosis, otitis, conjunctivitis, herpes, cavities, gingivitis, or the measles. Any of these infections can cause swollen lymph nodes in their affected area (ie. in the throat or side of the head). Lymph nodes usually react by increasing in size as the body fights the infection.
When this happens, it’s important not to touch the swollen area. Reactive lymph nodes slowly return to their original size once the underlying infection has resolved.
Acne occurs when the pores of the skin become blocked due to an overproduction of sebum, or oil. Sebum is made by the sebaceous glands, which are located at the base of the hair follicle, and can combine with dead skin cells to form a pimple. Pimples can often be painful and can become swollen.
Although it is not as frequent, acne can appear behind the ear, causing a lump that usually disappears on its own.
3. Sebaceous cyst
A sebaceous cyst is a type of fluid-filled lump that forms under the skin and is made up of a substance called sebum. These cysts can appear in any area of the body and are usually soft to the touch. When palpated, sebaceous cysts usually move and are not painful. Sebaceous cysts that become swollen, sensitive, red, or painful should be assessed by a dermatologist. Many times, the dermatologist may opt to perform a small procedure to remove the cyst.
A round, soft lump on the skin can also be a lipoma, a type of benign tumor made up of fat cells. These can also be removed through surgery or liposuction.
Mastoiditis is an infection in the bone located behind the ear. It can occur following an ear infection, especially if it wasn't treated correctly.
This condition is more common in children under the age of 2, but it can occur at any age. Mastoiditis is usually also associated with symptoms like headaches, decreased hearing, and fluid-like discharge from the ear.
A lipoma is a type of lump that doesn't cause pain or other symptoms. It is an overgrowth of fat cells which can appear anywhere on the body and typically grows slowly.
A lipoma is different in comparison to a sebaceous cyst because it is made-up of fat cells, while sebaceous cysts are made-up of sebum. Treatment for both of these lumps is the same, however, and usually involves surgical removal.
6. Swollen lymph nodes
Lymph nodes, also known as lymph glands, can be found throughout the body, and usually become swollen (or reactive) in the presence of infection or inflammation in the affected area. Lymph nodes also become swollen due to autoimmune diseases, the use of drugs, or even cancer of the head and neck, or lymphoma.
Swollen lymph nodes tend to have benign and temporary causes. They are usually pretty small, measuring a few millimeters in diameter (or about a fifth of an inch) and disappear within 3 to 30 days. If lymph nodes continue to grow, last longer than 30 days, or if you have other symptoms such as weight loss and fever, it’s important to go to the doctor for assessment and treatment as indicated.
When to seek medical assistance
It is recommended to go to the doctor if the lump appears suddenly, is fixed (ie. doesn't move when palpated), does not resolve, or presents with other signs and symptoms such as:
- Pain and redness;
- Increase in size;
- Releases pus or other fluid;
- Difficulty moving the head or neck;
- Difficulty swallowing.
In these cases, the doctor can inspect and palpate the lump, and assess any other symptoms (like fever and chills, which may indicate an infection). If the lump is painful, it may be a sign of an abscess or a pimple.
Treatment depends largely on the cause of the lump, which can disappear without any treatment or require antibiotics or surgical intervention.