Keratosis

In this month’s journal, we’re talking about one of the most common skin conditions, keratosis. We investigate the causes, what to look for and when to seek treatment.

Keratoses are growths of keratinocyte cells, which are responsible for the formation of keratinized skin. Let’s explore two of the main types of keratoses: seborrheic and actinic.

Seborrheic keratoses are common, benign skin growths.  They typically appear as pale, brown, or black ‘warty’ spots.  Most people will develop at least one seborrheic keratosis in their lifetime, often as they enter middle age.

Seborrheic keratoses can appear on any area of the skin except for the palms of the hands and soles of the feet. Commonly found on the back, chest, scalp, shoulders, groin, or abdomen, they are non-contagious and usually form slowly in groups but can also occur individually.

While the appearance of seborrheic keratoses can vary widely, there are some common characteristics to look for:

• Appearance: they may resemble raised moles, or warts, or appear as if they have been attached to the skin. In rare cases, they can resemble skin cancer.
• Colour: ranges from brown, black, or light tan, but can also be yellow or white.
• Shape: usually round or oval in shape.
• Size: they can vary in size, from very small to over one inch in diameter.
• Texture: initially, they may have a rough, bumpy surface that can easily crumble. Over time they may become thicker or become smooth and waxy.
• Sensation: seborrheic keratoses are generally not painful but can become itchy or irritated. Avoid scratching or picking at them, as this can cause bleeding and potential infection.

The exact causes of seborrheic keratoses are not fully understood but some of the recognised causes and risk factors include:

• Age: the risk of developing seborrheic keratoses increases with age, and it is more common in individuals aged 50 and over.
• Genetics: those with a family history of seborrheic keratosis are more likely to develop the condition, suggesting a genetic influence.
• Sunlight: seborrheic keratoses can appear following sunburn or dermatitis
• Skin friction: friction on the skin may contribute to the development of seborrheic keratoses, as they tend to occur in body folds.

In most cases of seborrheic keratoses, no treatment is required.  However, it is best to remove them if the growths are difficult to distinguish from skin cancer, if you are unhappy with their appearance, or if they become irritated by clothing or jewellery.

There are several options for removing seborrheic keratosis:

• Cryotherapy: liquid nitrogen is used to freeze the growths, causing them to fall off over time.
• Curettage: a small, sharp instrument called a curette is used to scrape off the growth.
• Electrosurgery: the growths are removed by cutting them off with a scalpel or using an electric current to cauterise and destroy the tissue.

The other common type of keratosis is actinic keratosis, also known as solar keratosis.  Actinic keratoses typically appear as rough, scaly patches on the skin, often found on sun-exposed areas such as the face, ears, scalp, and forearms. These patches can vary in colour from light pink to reddish-brown.

Prolonged exposure to ultraviolet (UV) radiation, primarily from the sun, is the leading cause of actinic keratosis. Those with fair skin or a history of frequent sunburn are more susceptible to developing these lesions. Chronic exposure to tanning beds or other artificial sources of UV radiation can also increase the risk.

Whilst they are very slow-growing, actinic keratoses should not be ignored as they have the potential to progress into a form of skin cancer known as squamous cell carcinoma. Various treatment options are available, depending on the severity of the condition.

• Topical medications: prescription creams or gels may be applied directly to the affected area to eliminate abnormal cells.
• Cryotherapy: liquid nitrogen is used to freeze and destroy the affected skin cells. The frozen tissue eventually falls off, allowing healthy skin to regenerate.
• Photodynamic Therapy (PDT): this treatment involves applying a photosensitising agent to the affected area, followed by exposure to a specific wavelength of light (or daylight). The combination of the agent and light destroys the abnormal cells.

If you have any concerns or questions about keratosis or notice other changes to your skin, consult a dermatologist who can advise on a treatment plan tailored to your needs.