A small bump on the head can be a surprising discovery, prompting immediate concern. While these lumps can be alarming, many head bumps are common and often do not indicate a serious health issue. Understanding the various reasons behind their appearance can provide clarity and help distinguish between a minor occurrence and something that might warrant medical attention.
Common Reasons for Head Bumps
One of the most frequent causes of a head bump is a direct injury, often called a “goose egg.” This swelling occurs when blood vessels under the skin rupture, leading to a hematoma in the scalp. The scalp’s rich blood supply means that even a minor impact can cause rapid and noticeable swelling. These bumps are temporary and resolve as the body reabsorbs the pooled blood.
Cysts are another common reason for bumps on the head, with epidermoid and pilar cysts being frequent types. Epidermoid cysts are slow-growing, benign sacs that form when skin cells, which normally shed, become trapped beneath the skin’s surface and continue to multiply. These cysts are filled with keratin, a protein found in skin and hair, and can appear on the scalp. While harmless, they may become inflamed, red, or painful if irritated or infected.
Pilar cysts, also benign, originate from hair follicles and are particularly common on the scalp. They present as smooth, movable, skin-colored nodules filled with keratin, and are painless unless they rupture or are injured.
Lipomas are benign fatty growths that appear as soft, movable lumps under the skin of the head. They are collections of mature fat cells and are harmless.
Folliculitis, an inflammation or infection of hair follicles, causes small, red, and sometimes pus-filled bumps resembling pimples. This condition results from bacterial or fungal infections and can cause itching or soreness. Scalp pimples, or acne, occur when hair follicles clog with dead skin cells, excess sebum, or hair product buildup, leading to inflammation. Insect bites can also cause a swollen, itchy bump on the scalp due to an allergic reaction.
Other Potential Causes
Beyond common explanations, other conditions can lead to head bumps. Osteomas are benign bony growths that can develop on the skull. While these bone spurs are slow-growing, they can cause discomfort depending on their size and location.
Dermatofibromas are small, firm nodules found on various parts of the body, though less common on the scalp. These growths are benign and may develop following minor trauma or insect bites. They are reddish-brown and do not cause symptoms, although some individuals may experience itching or tenderness.
Warts, caused by the human papillomavirus (HPV), are skin growths on the scalp. These can vary in appearance, being rough, scaly, or cauliflower-like. While less common on the scalp compared to other body areas, they are harmless.
When to Consult a Doctor
While many head bumps are benign, certain characteristics or accompanying symptoms warrant medical evaluation. A doctor should be consulted if a head bump rapidly changes in size, shape, or color. Any lump that becomes increasingly painful, tender, red, or warm to the touch, or if it begins to ooze pus or fluid, requires medical assessment.
Seek medical attention if the bump is accompanied by symptoms such as a worsening headache, persistent dizziness, confusion, vision changes, slurred speech, or weakness in the limbs. Nausea, repeated vomiting, or any clear fluid or blood draining from the nose or ears after a head injury also need immediate attention.
A bump that feels hard, fixed, or irregular, rather than soft and movable, should be evaluated by a healthcare professional. If the bump appeared after a significant head injury, especially with loss of consciousness or in infants or elderly individuals, prompt medical consultation is needed. Any head bump causing significant concern or discomfort warrants a discussion with a doctor.