Seborrhoeic keratoses

Who gets seborrhoeic keratoses?

Almost every Australian over 50 has at least one seborrhoeic keratosis. With increasing age, more seborrhoeic keratoses appear. It’s common for people over 75 to have dozens. Although seborrhoeic keratoses are especially common in older people, about a quarter of young adults (aged 15-30) have them.

Seborrhoeic keratoses can appear on most parts of the skin (but rarely on the palms, soles or genitals). They are more likely to appear on areas that have been exposed to sunlight, but they don’t always appear on these areas.

Seborrhoeic keratoses are more common in people whose parents or grandparents have many.

There is no known way of preventing them from appearing.

How are seborrhoeic keratoses diagnosed?

Usually a doctor can diagnose a seborrhoeic keratosis by looking at it and feeling its consistency. High-magnification examination with a dermoscope usually shows characteristic features.

Sometimes, seborrhoeic keratoses don’t exactly fit these criteria, and even an experienced doctor might find them challenging to identify. In some cases, they can look like skin cancers (melanoma or squamous cell carcinoma), and a small number of melanomas look like seborrhoeic keratoses and can potentially be missed.

If the diagnosis is uncertain, the spot should be biopsied. This is commonly done by shaving it off the surface of the skin. A skin pathologist can then examine the specimen to provide a diagnosis.

Treatment for seborrhoeic keratoses

Because seborrhoeic keratoses are harmless, medical treatment is not necessary. They are usually treated for cosmetic reasons or because they are itchy or irritated.

Unfortunately, seborrhoeic keratoses frequently return after treatment.

In many cases, seborrhoeic keratoses can be treated at home:

• Exfoliation: After soaking the seborrhoeic keratosis (in a bath or swimming), gently rub it with a rough object such as an exfoliating glove, pumice stone, emery board or even fine sandpaper. This treatment may need to be repeated several times but tends to give a good cosmetic result.
• Salicylic or lactic acid: These solutions can dissolve rough, dry and crusted skin,and help break down seborrhoeic keratoses. They are available over the counter or online without a prescription. Stronger concentrations of salicylic acid are more effective against seborrhoeic keratoses, but can lead to pigmentation abnormalities in the treated area.

Medical treatments for seborrhoeic keratoses include cryotherapy, laser surgery and radiofrequency surgery.

Complications

Seborrhoeic keratoses have no dangerous complications, but people often don’t like them because they may be itchy or unsightly, they can become irritated or get caught up in clothing, which can result in bleeding. Some people think of them as a reminder of ageing, even though they are also common in young people. The main medical concern is that in people with many seborrhoeic keratoses, it could be difficult to identify a new or changing melanoma or other skin cancer in a region surrounded by many other dark or raised spots.