A painful lump on the back of the head (the occipital region) can cause understandable concern, yet most causes are localized and benign. The sensation of a painful bump is a symptom resulting from various underlying biological mechanisms involving the skin, soft tissues, muscles, nerves, or the skull itself. Determining the source of the discomfort requires categorizing the issue based on the tissue layer from which the bump originates.
Skin and Soft Tissue Related Bumps
The most frequent causes of a painful bump on the back of the head are superficial, originating within the layers of the skin, hair follicles, or the subcutaneous fat just beneath the scalp. These conditions represent a distinct, palpable mass that is physically present.
Pilar cysts (trichilemmal cysts) are keratin-filled sacs that commonly develop around hair follicles on the scalp. These smooth, dome-shaped lumps are often painless unless they become irritated or rupture. They form when the hair follicle lining accumulates keratin, creating a closed sac under the skin.
A lipoma is a noncancerous tumor composed of fatty tissue. Lipomas are soft, rubbery, and often movable when gentle pressure is applied. While they grow slowly, they can cause a dull ache if they grow large enough to press against nearby nerves.
Infection of the hair follicles leads to folliculitis, presenting as small, red, tender bumps. If this infection progresses, it can result in a larger, deeper abscess—a collection of pus causing significant pain, redness, and warmth. Inflammation makes these particularly painful because it places pressure on the densely innervated scalp skin.
Temporary swelling can also result from insect bites or localized allergic reactions, where the body’s immune response causes a rapid influx of fluid. This creates a raised bump that is often itchy, tender, and sometimes accompanied by redness, distinguished by its rapid onset and tendency to resolve spontaneously.
Muscular Tension and Nerve Irritation
Sometimes, the perception of a painful bump is not a physical mass but rather a specific point of extreme tenderness caused by underlying muscular or neurological issues. These conditions create pain that is perceived as originating from a lump, even if a true growth is not present.
Occipital neuralgia involves the irritation of the occipital nerves, which run from the upper neck through the back of the scalp. This condition produces a characteristic sharp, shooting, or electric-shock-like pain originating at the base of the skull. The nerve pathway can become hypersensitive, making the scalp tender to the touch, which can feel like a painful bump.
The irritation often stems from the greater and lesser occipital nerves being compressed by overly tight suboccipital muscles in the upper neck. This nerve compression can be triggered by sustained poor posture or chronic neck tension. The pain can occur in brief, intense episodes, or it can manifest as a persistent ache between the episodes.
Chronic tension can also lead to the development of taut bands or knots, known as myofascial trigger points, in the suboccipital muscles. These trigger points feel like hard, firm nodules under the skin and are painful when pressed. While they are muscle tissue, they mimic the sensation of a hard, painful lump and can refer pain up the back of the head.
Bony Protrusions and Traumatic Injuries
Causes related to the skull structure itself can account for a painful bump, ranging from normal anatomical variations to the aftermath of a physical impact. These conditions involve either the bone or the tissues immediately covering it.
The external occipital protuberance (EOP) is a normal bony prominence located at the base of the skull where neck muscles attach. If this structure is pronounced, it can be mistaken for an abnormal growth. Pain typically arises from mechanical irritation, such as prolonged pressure or the tugging of the attached muscles.
A traumatic injury to the head can result in a scalp hematoma, commonly known as a “goose egg.” This is a collection of blood pooling between the scalp and the skull following a blow, causing rapid swelling. The resulting lump is acutely painful, bruised, and swollen due to internal bleeding and inflammation.
Less frequently, a hard lump may be an osteophyte, or bone spur, which is a small, bony projection that forms due to degenerative changes. While usually painless, they can cause discomfort if they interfere with surrounding soft tissue or nerves.
Warning Signs Requiring Prompt Medical Evaluation
While most painful bumps on the back of the head are minor issues, certain accompanying signs indicate the need for immediate medical consultation. These warning signs suggest a more serious underlying condition, such as a severe infection, internal injury, or a neurological complication.
Any painful bump that rapidly increases in size, changes color, or begins to ooze pus or discharge should be evaluated for a significant infection or inflammation. The presence of systemic symptoms, such as a high fever, chills, or spreading redness and warmth away from the lump, indicates a potentially serious infection requiring urgent treatment.
A bump appearing after a significant head trauma, even if the person did not lose consciousness, necessitates prompt medical attention to rule out a concussion or internal bleeding. Neurological symptoms are particularly concerning, including:
- Sudden severe headache
- Repeated vomiting
- Confusion
- Difficulty with speech or vision
These changes suggest potential pressure or injury affecting the brain. Pain that is unmanageable with over-the-counter medication, or a bump that persists without any improvement for several weeks, should also be examined by a healthcare professional.