Finding a lump on the back of your head can be concerning. While any new growth can be unsettling, many lumps in this area are harmless and do not indicate a serious health issue. This article provides general information about potential causes. It is important to remember this content offers broad insights and is not a substitute for professional medical advice.
Common Benign Causes
Many lumps found on the back of the head are benign. One frequent type is an epidermoid cyst, sometimes mistakenly referred to as a sebaceous cyst. These cysts develop from the outer layer of the skin, are often slow-growing, and contain keratin, a protein found in skin and hair cells. They usually present as firm, flesh-colored or yellowish, round nodules that can be fixed to the skin surface but mobile over deeper layers, sometimes with a central opening.
Another common type is the pilar cyst, also known as a trichilemmal cyst or wen. These cysts form around hair follicles, primarily on the scalp. Pilar cysts are smooth, movable lumps filled with keratin and are painless unless they rupture or become inflamed. They are flesh-colored nodules that can vary in size and may be present as single or multiple lesions.
Lipomas are soft, fatty lumps that develop just beneath the skin. These growths are soft and doughy to the touch, easily movable, and painless. They can occur anywhere on the body where fat is present, including the back of the head and neck.
Inflammation of hair follicles, known as folliculitis, or deeper infections called boils can also manifest as lumps on the back of the head. Folliculitis appears as small, red, inflamed bumps that can be pus-filled. Boils are more tender, red, and swollen areas that form around hair follicles, often accompanied by pus. Carbuncles, which are clusters of boils, can be larger and deeper.
A lump might be a normal part of the skull’s anatomy or a benign bony growth, such as an osteoma or exostosis. An osteoma is a benign bone tumor, while an exostosis is an outgrowth of bone. These bony prominences are hard and fixed in place. A lump can also result from trauma, leading to swelling or a hematoma, a collection of blood under the skin. These types of lumps appear immediately after an injury and resolve within a few days.
Less Common or Concerning Causes
While many lumps on the back of the head are benign, some less common or more serious conditions can also cause such growths. Swollen lymph nodes are one such possibility. Lymph nodes are small, oval-shaped glands that play a role in the immune system by filtering out foreign material like bacteria and viruses. The occipital lymph nodes, located at the base of the skull, can swell due to infections in the scalp, ear, or other parts of the body, or due to systemic illnesses. These swollen nodes feel like tender, movable lumps.
In rare instances, a lump on the back of the head could be a skin lesion or tumor. While most skin growths are harmless, some can be malignant. Basal cell carcinoma and squamous cell carcinoma are the most common types of skin cancer that can develop on the scalp. These appear as new or changing moles, scaly patches, or sores that do not heal.
Melanoma, a less common but more aggressive form of skin cancer, can also occur on the scalp and appears as an uneven, asymmetrical, or changing mole with irregular borders and varied colors. Scalp cancers, especially melanoma, can be harder to detect due to hair coverage.
When to Seek Medical Attention
Consult a healthcare professional if you discover a lump on the back of your head, especially if certain characteristics are present. Seek medical attention if the lump is painful, red, warm, or tender to the touch, as these could be signs of infection or inflammation. A visit to the doctor is also recommended if the lump is rapidly growing or changing in size, shape, or color.
Seek medical attention if the lump is accompanied by other symptoms such as fever, unexplained weight loss, night sweats, or persistent fatigue, which could indicate a systemic issue. If the lump appeared after a head injury and is associated with symptoms like dizziness, confusion, persistent headache, vomiting, or changes in vision, immediate medical evaluation is necessary. If the lump feels hard, fixed, and does not move under the skin, or if it persists for more than two weeks, seek medical assessment. Also seek advice if the lump is bothering you aesthetically or causing discomfort.
What to Expect at the Doctor’s Office
When you visit the doctor for a lump on the back of your head, the process begins with a thorough medical history and physical examination. The doctor will ask about when you first noticed the lump, any associated symptoms like pain or changes in size, and your general health history. They will then examine the lump, assessing its size, texture, mobility, and any signs of inflammation or tenderness. This initial assessment provides enough information for a preliminary diagnosis.
Depending on the findings from the physical exam, the doctor may deem further diagnostic tests necessary. These could include imaging studies such as an ultrasound, MRI, or CT scan, which provide detailed views. In some cases, a biopsy might be performed, where a tissue sample is taken from the lump for analysis. After reviewing all the information, your doctor will discuss the diagnosis with you and outline potential management options, which may range from observation to medication or surgical removal if indicated.