Seborrhoeic keratoses are common, harmless skin growths that usually appear during adult life. They are sometimes called seborrhoeic warts, but they are not caused by a virus, are not contagious and do not turn into skin cancer.
Appearance
They may be flat or raised, smooth or rough, and range from skin-coloured to tan, brown or almost black. Many have a waxy, scaly or “stuck-on” appearance. They commonly occur on the chest, back, scalp, face or neck and may appear singly or in groups.
Why they develop
The exact cause is not fully understood. They become more common with age and may run in families. They are different from actinic keratoses, which are rough sun-damaged patches with a small risk of becoming skin cancer.
Diagnosis
A clinician can often identify a seborrhoeic keratosis by examining it. Some growths can resemble melanoma or another skin cancer. Dermoscopy or a small skin sample may be needed when the diagnosis is uncertain.
Does it need treatment?
No treatment is needed when the diagnosis is clear and the growth causes no problems. A clinician may remove it if it repeatedly catches on clothing, becomes irritated or itchy, or if there is uncertainty about the diagnosis. Methods include freezing, scraping, cautery or minor surgery. Removal can leave lighter or darker skin or a scar.
When to seek medical advice
Have a new or changing growth checked if it has an irregular shape or colour, grows quickly, repeatedly bleeds, develops a sore, looks unlike your other marks, or remains inflamed. Do not try to burn, cut or freeze an uncertain skin lesion at home.
Sources
- Newcastle Hospitals NHS Foundation Trust: Seborrhoeic Keratosis
- DermNet: Seborrhoeic keratosis
- NHS: Actinic keratoses
Reviewed: 28 August 2026