Irregular Appearing Scalp: Bumps, Ridges and Bony Irregularities

This page covers bumps, ridges and lumps you can feel. For patches, scaling, redness and hair loss on the scalp skin, see irregular appearing scalp: skin conditions.

What scalp irregularities are

The scalp is the skin and hair over the skull. The skull itself is made of several bony plates joined at seams called sutures. Its surface is rarely perfectly smooth. Most adults can feel bumps and ridges if they run their fingers firmly over their head. The question is whether an irregularity is part of the normal shape, comes from the skin or the tissue under it, or comes from the bone.

Normal skull bumps and ridges

• External occipital protuberance: a bony knob at the back of the head, more prominent in men. Some people have a larger, more pointed version sometimes nicknamed a "bun".
• Sutural ridges: slight ridges along the joints between skull bones, especially along the top (sagittal suture).
• Temporal lines: faint curved ridges on the sides of the skull where the chewing muscles attach.
• Asymmetry: most skulls are slightly uneven, and one side may bulge more.

These are present all your life, do not change and need no treatment. People often notice them for the first time when washing hair or after a haircut.

Common lumps causing bony-feeling irregularities

Osteoma

An osteoma is a small, slow-growing, harmless growth of normal bone on the outer skull, usually on the forehead or top of the head. It feels rock-hard, painless and fixed. Most need nothing. If it is large or cosmetically bothersome, it can be removed surgically. Many osteomas, or osteomas with bowel polyps, can be part of a rare inherited condition called Gardner syndrome.

Pilar and epidermoid cysts

Pilar cysts are the commonest scalp lump: smooth, firm, round and movable, often several, frequently running in families. They are filled with keratin. Epidermoid cysts are similar and sometimes have a small central pore. Both can become inflamed and painful. They are removed by a minor procedure if bothersome. Many people call these "sebaceous cysts".

Lipoma

A lipoma is a soft, rubbery, painless fatty lump that slides under the skin. On the forehead and scalp, lipomas can sit under the muscle layer and feel firmer.

Dermoid cysts

Present from birth, dermoid cysts are commonly found at the outer edge of the eyebrow or along the midline of the skull. They are removed surgically.

Less common causes

• Healed skull fracture: a step or dent after a past injury.
• Paget disease of bone: abnormal bone remodeling in older adults that enlarges and thickens the skull, sometimes with headaches, hearing loss and a hat size that increases.
• Cutis verticis gyrata: thick folds of scalp skin that look like the surface of the brain. It can be inherited or linked to other conditions.
• Hematoma: a firm "goose egg" after a knock, which usually softens and disappears over 1 to 3 weeks.
• Bone tumors and metastases: rare, but a hard, growing, sometimes painful skull lump in someone with a history of cancer needs imaging.
• Skin cancers: basal cell carcinoma and squamous cell carcinoma often appear on sun-exposed scalps, especially with thinning hair. See basal cell carcinoma.

Irregular scalp in babies

A newborn's skull bones can overlap after birth, making ridges that smooth out within days to weeks. Babies who lie in one position can develop a flattened area (positional plagiocephaly), which improves with tummy time and repositioning. A hard ridge along a suture with a progressively abnormal head shape may be craniosynostosis, early fusion of a skull seam, which needs a pediatric specialist.

How a doctor checks a scalp irregularity

A doctor will ask how long it has been there, whether it has changed, and about injuries and cancer history. They will feel whether it is hard or soft, moves or is fixed, and look at the skin. Ultrasound shows whether a lump is a cyst, fat or solid. X-ray or CT shows bone. A biopsy is taken from any suspicious skin growth.

Treatment and cure

Normal skull variations need no treatment. Cysts and lipomas can be cut out under local anesthetic if they are bothersome or inflamed. Osteomas are removed only if large or troublesome. Skin cancers are removed surgically. Paget disease is treated with bisphosphonate medicines.

Frequently asked questions

What causes bony irregularities on the scalp?

Most are normal features of the skull, such as the bump at the back of the head, ridges along the sutures and natural asymmetry. Others are osteomas, healed fractures and, in older adults, Paget disease. Firm lumps that move under the skin are usually cysts.

Is it normal to have ridges on your skull?

Yes. Faint ridges along the skull seams and a bony bump at the back of the head are normal and present throughout life. See a doctor only if a ridge is new, growing, painful, or appeared after an injury.

What is a hard bump on my head that doesn't move?

A hard, fixed, painless bump that has not changed for years is usually an osteoma or a normal part of the skull. A pilar cyst can feel hard but usually moves slightly. Any hard lump that is growing should be checked with imaging.

How are scalp irregularities treated?

Normal skull shapes need no treatment. Cysts, lipomas and osteomas can be removed with minor surgery if they bother you. Skin cancers are removed surgically. Underlying conditions such as Paget disease are treated with medication.