What should you know about crusty cyst on scalp?

Pilar cysts develop from cells associated with hair follicles and commonly form as smooth, firm lumps beneath the scalp. Friction, scratching, inflammation, or an opening in the skin can leave a crust over the bump. A crust does not identify the lump by itself; a clinician may need to feel it and inspect the surface. A tender, warm, swollen area can indicate inflammation or infection, while bleeding, rapid change, or an irregular surface deserves prompt review.

Do not pick at the crust or try to drain the lump with a needle. This can introduce bacteria, worsen inflammation, and make later assessment harder. Other types of scalp lumps can look similar, so use the symptom guide for [Skin Lumps](/symptoms/skin-lumps/).

Keep the area clean with gentle washing and pat it dry. Avoid tight headwear, harsh hair products, and scratching over the lesion. If it catches on a comb, protect it from friction without sealing it under an occlusive dressing. Book a dermatology appointment, particularly if the lump is painful, repeatedly crusts, or interferes with washing or sleep. If removal is advised, [Cyst Removal](/treatments/surgical-dermatology/cyst-removal/) can explain how a clinician removes the cyst and its surrounding capsule to reduce the chance of it returning.

Seek prompt medical care for spreading redness, increasing warmth, pus, fever, marked pain, or swelling near the eye or neck. Arrange an earlier assessment if the lesion bleeds without being disturbed, develops a persistent open sore, becomes fixed, or changes quickly. An emergency service is appropriate for severe illness, rapidly spreading swelling, or difficulty breathing.

Ask whether the lump feels like a pilar cyst, whether infection is present, and whether it needs observation, medication, drainage, or complete removal. Also ask how to wash the area, what symptoms should trigger urgent review, and whether a removed lesion will be examined in the laboratory.