Seborrhoeic Keratoses (Senile Warts): Symptoms, Causes & UK Management

Seborrhoeic keratoses (singular: keratosis) are extremely common, non-cancerous skin growths. In the UK, they are frequently referred to as 'senile warts', though this term is becoming less common as they can appear as early as your 30s or 40s. They are also sometimes colloquially known as 'barnacles of ageing'.

Unlike viral warts, seborrhoeic keratoses are not contagious and are not caused by a virus. Instead, they are a result of a build-up of skin cells. They can appear anywhere on the body, except the palms and soles of the feet, and most commonly develop on the chest, back, shoulders, or face. While they are medically harmless (benign), their appearance can cause concern for patients who worry they might be a sign of skin cancer.

How do they look and feel?

Seborrhoeic keratoses have a very distinct appearance that often allows a clinician to identify them at a glance. Characteristic features include:

• 'Stuck-on' appearance: They look like they have been pressed onto the skin, much like a piece of wax or a small scab.
• Texture: Initially, they may be smooth or slightly flat, but over time they often become thickened, warty, or crumbly.
• Colour: They vary significantly in pigment, from pale sand and yellow to dark brown or even blue-black.
• Shape: Usually oval or round, ranging in size from a few millimetres to over two centimetres across.
• Number: It is common for people to develop multiple growths over many years, sometimes appearing in crops.

Most of the time, these growths are entirely asymptomatic. However, if they are located in areas where clothing rubs (such as the waistline or under bra straps), they can become itchy, irritated, or may bleed if accidentally scratched.

The exact cause of seborrhoeic keratoses remains unknown, though several factors are heavily implicated in their development. According to the Primary Care Dermatology Society (PCDS) in the UK, the most significant factor is simply ageing. They are rarely seen in children but are found in the majority of adults over the age of 60.

There is also a strong genetic component; if your parents had many seborrhoeic keratoses, you are more likely to develop them yourself. While sun exposure is often blamed for skin changes, the relationship with UV light is less clear for these specific growths, as they frequently appear on areas of the body that are rarely exposed to the sun. Unlike some other skin lesions, they are not related to any underlying internal health condition or hygiene habits.

Because seborrhoeic keratoses can sometimes mimic the appearance of skin cancer—specifically melanoma or pigmented basal cell carcinomas—getting a professional opinion is essential for peace of mind. You should consider booking a consultation with an online GP if:

• A growth changes rapidly: If a lesion changes shape, size, or colour over a few weeks.
• Multiple colours: The growth has an irregular border or contains many different shades.
• Inflammation: The area becomes red, swollen, or develops a crust without being provoked.
• Uncertainty: You are simply unsure what the growth is and want a specialist review.

Our online GP service can review high-quality photos and descriptions of your skin lesions. While a definitive diagnosis of some pigmented lesions requires an in-person dermoscopy (using a specialised magnifying tool), an online GP can often provide reassurance or advise you if a face-to-face urgent referral via the NHS 'two-week wait' pathway is necessary.

In the United Kingdom, seborrhoeic keratoses are considered a cosmetic issue by the NHS. Under NICE (National Institute for Health and Care Excellence) guidelines, treatment is generally not funded on the NHS unless the diagnosis is in doubt or the lesion is causing extreme functional problems (e.g., catching and bleeding constantly).

If you wish to have them removed for cosmetic reasons, you will likely need to seek private treatment. Common methods include:

• Cryotherapy: Freezing the growth with liquid nitrogen. The lesion usually scabs over and falls off within a week or two.
• Curettage and Cautery: Scraped off under local anaesthetic and the base heat-sealed to prevent bleeding.
• Laser Treatment: Using light energy to destroy the tissue.
• Excision: Cutting the lesion out, though this is rarely necessary for benign keratoses.

It is important to note that even after successful removal, new seborrhoeic keratoses may develop in the same area or elsewhere on the body in the future.

The biggest concern for most patients is telling the difference between a harmless 'senile wart' and a malignant melanoma. Melanoma is a serious form of skin cancer that requires urgent intervention. While a seborrhoeic keratosis typically has a well-defined 'stuck-on' edge and a uniform matte or warty surface, melanomas tend to be flatter, have blurred or irregular edges, and may show a variety of colours (reds, whites, and greys alongside blacks and browns).

If you notice the 'ugly duckling' sign—a lesion that looks completely different from all your other spots—you must have it assessed by a doctor immediately. Never attempt to remove or 'scratch off' a skin growth yourself, as this can lead to infection, scarring, and may obscure a diagnosis if the lesion is actually a malignancy.