A painful bump on your head is usually one of a few common things: a cyst that’s become inflamed, an infected hair follicle, a bump from hitting your head, or occasionally a bony growth. Most painful scalp bumps are benign and treatable, but the cause matters because each one behaves differently and calls for a different response.
Cysts: The Most Common Scalp Bumps
Cysts are the single most frequent cause of lumps on the scalp. Two types dominate: epidermoid cysts (sometimes called sebaceous cysts) and pilar cysts. Epidermoid cysts outnumber pilar cysts about four to one. Both grow slowly, feel firm to the touch, and sit just beneath the skin. A pilar cyst typically feels smooth and flesh-colored, and it can appear anywhere on the head, though the scalp is the most common location. Women over 60 develop them more often, and some grow quite large, occasionally reaching 8 cm or more.
Here’s the important part: cysts on the scalp don’t usually hurt on their own. They become painful when something goes wrong. A cyst can rupture spontaneously, leaking its contents into the surrounding tissue and triggering inflammation. It can also become painful if it grows large enough to press against the skull, or if you’ve tried to squeeze or pop it. Attempting to drain a cyst yourself is one of the fastest ways to introduce bacteria and cause an infection. Signs that a cyst has become infected include tenderness, warmth over the area, redness spreading around the bump, and fever above 100.4°F.
If a cyst is bothering you, a doctor can remove it with a minor surgical procedure under local anesthesia. The key is removing the entire outer wall of the cyst. If any of that wall is left behind, the cyst tends to grow back. You may be referred to a dermatologist or surgeon for this.
Infected Hair Follicles and Boils
Folliculitis, an infection of the hair follicle, is another common culprit. It shows up as clusters of small, pimple-like bumps around hair follicles, often with pus inside. The skin around them feels tender, sometimes itchy or burning. The most common cause is staph bacteria getting into a damaged follicle, though fungi can also be responsible.
When a follicle infection goes deeper, it becomes a boil (also called a furuncle). Boils tend to appear suddenly as a single, painful, swollen lump. They’re warm to the touch and often develop a visible head of pus over several days. A carbuncle is a cluster of boils that merge together, and these are more serious. Boils on the scalp can be especially uncomfortable because there’s little cushioning between the skin and the skull. Mild folliculitis often clears on its own with warm compresses and good hygiene, but boils that keep growing or don’t drain on their own typically need medical attention.
Bumps From Injury
If you bumped your head recently, the painful lump is likely a hematoma, commonly called a “goose egg.” This is a pool of blood that collects outside damaged blood vessels beneath the skin. The scalp has a rich blood supply, which is why even a minor knock can produce a surprisingly large bump.
Your body heals a hematoma by sending specialized cells to break down the trapped blood so it can be reabsorbed through your lymphatic system. Most hematomas resolve within one to four weeks. Applying ice in the first 24 to 48 hours can help reduce swelling. A goose egg that doesn’t shrink after several weeks, or one accompanied by confusion, vomiting, vision changes, or worsening headache, warrants prompt medical evaluation.
Bony Growths on the Skull
Sometimes a hard, immovable bump on the head turns out to be bone rather than soft tissue. Osteomas are benign bony growths that develop on the skull’s surface. They grow slowly and are often discovered by accident, but pain is actually the most frequently reported symptom when people do seek medical attention for them. Unlike cysts, which feel somewhat movable under the skin, an osteoma feels rock-hard and fixed in place because it’s attached directly to the skull. Diagnosis typically requires imaging, usually a CT scan, which shows a smooth, well-defined, dense mass on the bone’s surface.
Nerve Pain That Mimics a Bump
Occasionally what feels like a painful bump is actually nerve inflammation rather than a true lump. Occipital neuralgia occurs when the nerves running from the base of the skull through the scalp become irritated or swollen. This can produce sharp, electric-shock-like pain, burning sensations, or throbbing that starts at the back of the head or behind one eye. You might feel a tender spot on your scalp and assume there’s a bump when the issue is actually the nerve beneath it. If your pain is intermittent, shoots along a line from the back of your head, or feels like a sudden jolt, nerve involvement is worth considering.
How to Tell What You’re Dealing With
A few characteristics can help you narrow down the cause before you see a doctor:
- Soft and movable under the skin: likely a cyst or lipoma
- Red, warm, with pus or a visible head: likely folliculitis or a boil
- Appeared after hitting your head: likely a hematoma
- Rock-hard and completely fixed: likely a bony growth like an osteoma
- No visible bump but sharp, shooting pain: possibly nerve-related
Size changes matter. Cysts and osteomas grow slowly over months or years. Boils develop over days. Hematomas appear within hours of an injury and gradually shrink. A bump that grows rapidly without an obvious cause, has irregular borders, or is firmly fixed to deeper tissue is more concerning and should be evaluated promptly. While malignant scalp lesions are uncommon, they can mimic the appearance of benign cysts, so any atypical or fast-changing lump warrants a professional look. When there’s doubt, a biopsy remains the definitive way to confirm what a scalp lump actually is.
What Not to Do
Resist the urge to squeeze, pop, or cut into a scalp bump at home. With cysts, this almost always leads to infection and recurrence because the cyst wall stays intact beneath the skin. With boils, squeezing can push bacteria deeper into the tissue or into the bloodstream. Even if a bump looks like it has an obvious head of pus, the scalp’s dense blood supply means infections here can escalate quickly. A warm, damp cloth held against the area for 15 to 20 minutes several times a day is the safest thing you can do at home while you decide whether to see a provider.