Seborrhoeic Keratoses (Seborrhoeic Warts): UK Symptoms and Treatment Guide

Seborrhoeic keratosis (plural: keratoses) is one of the most common non-cancerous (benign) skin growths in older adults. In the UK, they are sometimes informally referred to as seborrhoeic warts or 'senile warts', although they are not caused by a virus and are not contagious like true viral warts. They are essentially a build-up of ordinary skin cells that have become thickened and pigmented.

These growths typically appear on the face, chest, shoulders, or back. They develop slowly and often start as small, rough bumps before thickening and developing a waxy, 'stuck-on' appearance. While they can look concerning to the untrained eye, especially if they are very dark in colour, they are medically harmless and do not lead to skin cancer. However, because they can mimic the appearance of melanoma, it is vital to understand how to identify them and when to seek professional advice.

Seborrhoeic keratoses vary greatly in appearance, but there are several hallmark features that help UK GPs and clinicians identify them. Understanding these can help ease anxiety about new skin marks.

• Texture: They often start as small, grainy bumps but eventually develop a waxy, scaly, or 'crusty' surface.
• Shape: They are usually round or oval-shaped.
• 'Stuck-on' Look: Many patients describe the lesion as looking like it has been pressed onto the skin like a piece of warm candle wax or a small barnacle.
• Colour: They range from light tan and yellow to deep brown or even pitch black. A single person may have multiple keratoses of different colours.
• Size: They can be tiny (a few millimetres) or grow to more than an inch (2.5 cm) across.

While they are usually painless, a seborrhoeic keratosis may become itchy or inflamed if it is located in an area where it is frequently rubbed by clothing, such as under a bra strap or along a waistband.

The exact cause of seborrhoeic keratosis remains unknown, though several factors are believed to play a role. According to NHS and British Association of Dermatologists (BAD) guidance, the following factors increase the likelihood of developing these growths:

• Age: They are most common in people over the age of 50. It is rare to see them in children or young adults.
• Genetics: There is strong evidence that a tendency to develop many seborrhoeic keratoses runs in families.
• Sun Exposure: While not a direct cause (as they often appear in non-sun-exposed areas), some research suggests UV light may play a role in their development on the face and arms.

It is important to note that seborrhoeic keratoses are not related to skin hygiene, diet, or any underlying internal illness. They are simply a natural part of the skin’s ageing process for many people.

While seborrhoeic keratoses are benign, the primary challenge for patients is distinguishing them from skin cancers, such as melanoma or basal cell carcinoma. If you notice a new growth, you should speak to a GP online or in person to confirm the diagnosis.

Why use an online doctor for skin checks?

An online GP consultation is a convenient way to get an initial assessment of a skin lesion. During a video call, a doctor can examine the growth, ask about its history, and determine if it has the typical features of a seborrhoeic wart. You should specifically seek advice if:

• A growth appears suddenly and scales up rapidly.
• The growth has irregular borders or multiple colours.
• The lesion bleeds, oozes, or refuses to heal.
• The growth is causing you significant psychological distress or physical discomfort.

The GP may ask you to provide high-resolution photographs to assist with the diagnosis. In line with NICE (National Institute for Health and Care Excellence) guidelines, if there is any doubt about the nature of the lesion, you will be referred for a face-to-face dermatoscopy or a specialist review.

In most cases, a UK GP or dermatologist can diagnose a seborrhoeic keratosis simply by looking at it. They may use a tool called a dermatoscope—a handheld magnifying device with a light—to see the internal structures of the skin. Characteristic features visible under a dermatoscope include 'horn cysts' and 'comedo-like openings', which are virtually diagnostic for these benign growths.

If a lesion is particularly dark or has changed rapidly, a clinician might recommend a skin biopsy. This involves removing a small piece of the growth (or the whole thing) under local anaesthetic and sending it to a laboratory for histology to ensure no malignant cells are present.

Because seborrhoeic keratoses are harmless, treatment is usually not required. However, if they are unsightly or catch on clothing, several removal options are available. Please note that on the NHS, removal is rarely funded as it is considered a 'cosmetic' procedure unless the growth is severely inflamed or causing functional problems.

Common Removal Methods:

• Cryotherapy: The growth is frozen with liquid nitrogen. Over the following days, the keratosis blisters and falls off. This may leave a temporary or permanent pale mark on the skin.
• Curettage and Cautery: The area is numbed with local anaesthetic, and the growth is scraped away with a spoon-shaped instrument (a curette). Heat (electrocautery) is then used to stop any bleeding.
• Laser Therapy: Certain types of lasers can vaporise the growth, though this is usually only available through private dermatology clinics.

Warning: Never attempt to 'scratch off' or remove a skin growth yourself. This can lead to infection, scarring, and most importantly, it prevents a proper medical diagnosis of the lesion.