What Is This Lump on the Back of My Neck? (Top 9 Causes)

Updated in December 2023

A lump on the back of the neck may be a muscle knot, which occurs when the muscle contracts incorrectly and does not return to its normal relaxing position. Inflammation, from a boil from example, or an infection, like mononucleosis, can also cause a lump. 

Depending on what caused it, a lump on the back of the neck can present with other symptoms, like heat upon palpation of the lump, redness, sensitivity to touch, pus or a fever. 

If you notice a lump on the back of your neck, you should see a family doctor or dermatologist to assess its characteristics as well as any other symptoms you may have. Once a diagnosis is identified, appropriate treatment can be initiated. The doctor may advise antibiotics, anti-inflammatories or even surgical removal. 

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Common causes

The most common causes of lumps on the back of the neck are:

1. Muscle knot

A muscle knot occurs when the muscle contracts incorrectly and does not return to its normal relaxing position. This can cause a lump on the neck muscles, as well as other symptoms like pain and discomfort that can radiate to the arm. The arm may be additionally affected, with tingling, loss of strength and pain with movement. 

A muscle knot can happen after carrying excessively heavy weight on the shoulders, like a heavy backpack. They can also emerge after intense exercise without a proper warm-up, or even from stress. 

What to do: You can massage the affected muscle with firm and circular movements using a moisturizing cream or relaxing essential oil. You can also apply heat to the area for 15 to 20 minutes, 2 or 3 times a day. Stretching the neck can also help alleviate pain. Check out these easy back and neck stretches you can use to relieve tension at home. 

If the lump and discomfort do not resolve with these conservative measures, you should see a doctor, who may consider prescribing anti-inflammatories, muscle relaxants and/or physiotherapy. 

2. Sebaceous cyst

A sebaceous cyst is a round lump that forms under the skin. It usually is less than a few centimeters, but it can grow in size over time. These cysts can be soft or hard, and are moveable upon palpation. They can be found on the back of the neck, or on any part of the body.

Sebaceous cysts are benign and are form due to blocked sebaceous glands. Sebum starts to accumulate under the skin, forming a lump. Although they are generally not associated with symptoms, they can become inflamed, painful, red and hot or sensitive to the touch.

What to do: There is usually no specific treatment required when sebaceous cysts are small. The dermatologist may advise you to apply a warm compress over the cyst for 15 minutes to promote rupture on its own. Surgical removal may be an option for larger cysts or for cosmetic reasons. If the sebaceous cyst becomes inflamed or infected, the doctor may drain the cyst to remove the fluid and prescribe antibiotics. 

3. Boil 

A boil is a pus-filled lump that can grow over time. They are associated with symptoms like pain, heat around the boil, redness and sensitivity to the touch. Boils can emerge on the back of the neck or any part of the body that experiences increased friction. 

Boils can form due to inflammation at the root of a hair follicle, due to an obstructed sebaceous gland or from a wound in the neck area. Most boils occur due to a bacterial Staphylococcus aureus infection, which is naturally found on the skin and within the mucus membranes.

What to do: You can apply a warm, wet compress three times a day and wash the area well with warm water and mild soap. You should never attempt to rupture a boil, as it can worsen the inflammation and infection, making it more difficult to treat. In most cases, a dermatologist will recommend drainage of the fluid followed by antibiotic use. 

Check out other ways you can heal a boil quickly at home. 

4. Lipoma

A lipoma is a soft, round lump that forms under the skin. It is made-up of fat cells, and can grow on the neck, back, shoulders, armpits or anywhere on the body that contains fat cells. 

Generally, lipomas are painless, however there are cases in which in can grow and press on the nerves surrounding it. These lipomas can become inflamed, red and hot to the touch. Read more about the symptoms of a lipoma and what can cause them.

What to do: Generally, treatment is not necessary for lipomas. However, it can be surgically removed if it grows to a large size or if patients desire removal for cosmetic reasons.

5. Inflamed lymph nodes

Inflamed lymph nodes in the neck area can be felt as a small lump under the skin. These lumps can be painful, red and sensitive to the touch, and are often accompanied by a fever. 

Swollen, or reactive, lymph nodes typically indicate inflammation in the area, but can also emerge due to auto-immune diseases, medication use, cancer, or lymphoma. Learn more about what causes swollen lymph nodes and what you can do to treat them.

What to do: Treatment should be directed by a family doctor and will depend on the cause of the inflamed lymph nodes. The doctor may prescribe medications like anti-inflammatories, antibiotics, antivirals or corticosteroids to treat any underlying infection or inflammation. In cases of cancer, the doctor may opt to surgically remove lymph nodes containing cancer cells or tumors that are causing swelling. These types of procedures are usually followed by sessions of chemotherapy or radiation therapy. 

6. Folliculitis keloidalis 

Folliculitis keloidalis is a chronic inflammation of the root of a hair follicle that can cause round, solid lumps that measure less than 1 cm. They are usually found along the hair line and are associated with swelling, itchiness, scarring and even hair loss in the area. 

This type of scarring is more common in men with thick, curly hair. It can also occur due to chronic skin inflammation, prolonged friction from shirt collars, frequent hair cuts or shaving your hair. 

What to do: You should avoid shaving your head and using tight shirt collars to prevent friction among hair strands in the area. It is also important to keep the area clean and to use mild soap when cleansing. If the lump does not improve, you should see a dermatologist, who may recommend, corticosteroids, antibiotics, laser hair removal or even surgery. 

7. Infectious mononucleosis 

A lump on the back of the neck may occur with infectious mononucleosis. Also known as the "kissing disease" or simple "mono", this infection is caused by the Epstein-Barr virus and is transmitted through saliva. It is associated with swollen lymph nodes, sore throat, fever, constant headache, and white plaques within the mouth, tongue or throat. 

What to do: You should rest and ensure plenty of fluid intake to speed-up recovery, as there is no specific treatment for mono. The family doctor may prescribe anti-inflammatories to manage inflamed lymph nodes and fever. 

8. Allergies 

An allergy is an inflammatory reaction that emerges due to an exaggerated immune response. It can be triggered by substances like shampoo, conditioner, sunscreen or even certain clothing fabric. In addition to one or several raised bumps on the back of the neck, skin allergies may also present with irritated skin, itchiness and a red rash. 

What to do: It is important to identify the allergy trigger, so that symptoms can be prevented before they erupt. If your symptoms do not improve on their own, you should see a dermatologist for allergy testing, so that the triggering substance can be confirmed. The dermatologist may prescribe anti-allergenic or corticosteroid medication to help manage symptoms. 

9. Lymphoma

A lump on the back of the neck can be associated with lymphoma, which is a type of cancer that affects the lymph nodes. These lumps are usually firm and persist for over 1 to 2 months. They usually grow continuously and can cause other symptoms like fever, night sweats, excessive fatigue and weight loss for no apparent reason. 

What to do: You should see a family doctor, hematologist or oncologist for diagnosis though blood work, CT-scans or PET-scans. This will help to identify the type of lymphoma present and indicate the most appropriate treatment, which usually involves chemotherapy or radiation therapy.