AK is not OK! |

What is AK ?

AK stands for Actinic Keratosis. Other names for AK are solar keratosis or “sun spots”. Actinic Keratoses (AKs) are precancerous lesions predominantly found on chronically sun-exposed areas of the body (e.g. face, scalp, ears and the back of hands).^1-3

It is important to identify and treat these lesions because if left untreated they can develop into invasive squamous cell carcinoma (SCC) which is a type of non-melanoma skin cancer.^{1, 2}

Due to the amount of sun exposure, Australia has one of the highest rates of skin cancer in the world.¹

AKs mainly occur in areas most exposed to the sun, such as the scalp, face, ears, and extremity of upper limbs.¹

What does Actinic Keratosis look like?

AK can present as a single lesion or a small number of isolated lesions. They may vary in shape and colour.
They can look like small blemishes, scabs or spots that may appear gradually.
They are dry and rough most of the time and often red or brown in colour.
At the more advanced stage, the lesions can become ulcerated and swollen, and begin to bleed or weep.^1-4

Consult your Doctor if you notice an AK or a change in your skin that feels or looks unusual.

Images courtesy of Pierre Fabre (with rights to images as supplied by dermaweb.com)

Australians with AK have on average 6 to 8 visible AK lesions.⁵

Is the number of visible AK lesions important? Yes!

There are many reasons why the number of visible lesions is important:

The presence of multiple AKs indicates that there has been significant ultraviolet (UV) light exposure to that area of the skin.¹
The presence of multiple AKs is an indicator that, in this area of the skin, not only are there multiple visible precancerous lesions, but it is also likely that there are multiple subclinical (eg: non-visible, non-palpable) AK lesions present as well. This area of sun damage is called “field cancerisation”.^4,6,7
The risk of developing cancerous lesions (SCCs that can spread) increases as the number of AK lesions increases. ⁵

There are lesions that you can see and lesions that you cannot.
An ultraviolet camera can reveal the extent of sun damage.

Illustration showing the layers of the skin and how AKs develop.

AK lesions can regress spontaneously or stay at an early stage, but some of them can evolve into skin cancer in the form of invasive SCC. The biggest concern with SCC is that it can metastasise. Metastatic SCC accounts for about 20% of skin cancer deaths. ^1,5

Why Treat AK?

The primary goal of treatment of AKs is to prevent skin cancer ⁸

As it is not possible to predict which AK lesion will develop into an invasive SCC, treatment should aim to:^4,9

Reduce the risk of developing an invasive SCC
Eliminate as many visible and non-visible AK lesions as possible, thus reducing the extent of field cancerisation
Reduce the rate of AK recurrence

What are the treatments for AK ?

Lesion-directed therapies which treat individual lesions only^1-5

Freezing

CRYOTHERAPY

This is the technique most widely used by dermatologists to treat isolated AK. Liquid nitrogen is applied directly to the lesion at a temperature of -196°C and forms ice crystals. This kills the cells in the epidermis (keratinocytes) and the lesion falls off the skin

Surgical
therapy

There are lots of ways to surgically remove AK lesions and they can be quite painful. Excision (cutting away) and curettage (scraping) are only used for hyperkeratotic lesions (the most prominent). Dermabrasion is a bit like planing the surface of the skin, and is widely used to treat AK on the forehead and scalp

2. Field-directed therapies which treat multiple visible and non-visible lesions, that is they treat the area of field cancerisation. With field-directed therapies, non-visible subclinical lesions can become visible as they respond to treatment.^1-5,10

Topical
treatments

CREAMS, GELS, AND OINTMENTS

There are several options of topical treatments that are applied directly to the lesions.

These treatments can target several lesions at once and can be applied to the whole field cancerisation

Light
therapy

PHOTODYNAMIC THERAPY

This technique destroys the lesions by applying a photosensitiser which, when activated by light, releases a toxic agent into the AK lesions

Who is at risk of developing AK ?

Anyone can develop AK, however it is more common in certain situations.^5,6

The sun’s UV rays are a key factor in causing AKs to develop. In the long term, they can damage the DNA of cells and induce the development of skin cancer.

People who are at higher risk are those who:

Are fair skinned. Fair-skinned people are more likely to be affected because they have less natural protection

Have spent a long time exposed to the sun

Are over 40 (up to 50% of Australians over 40 of caucasian origin will have AK, increasing to up to 80% in the over 60s age group)

Are male (Historically, males tend to spend more time working outdoors - which places them at a higher relative risk of exposure to harmful rays. A balding scalp will also increase sun exposure)

Are taking immunosuppressant therapy

Ways to protect your skin from developing AK

The most common problem is sunburn, which can vary in severity.
Repeated over-exposure to the sun also speeds up the skin ageing process (premature wrinkles, blemishes, etc.).
Fortunately, there are lots of ways to keep well protected from the sun:¹¹

Limit your exposure to the sun when UV rays are strongest

Wear long sleeves, pants or skirts, a hat, and sunglasses

Apply sunscreen 20 minutes before going out, then every 2 hours, to all exposed areas, not forgetting your ears, hands, and neckline

Use sunscreen with a high sun protection factor that is waterproof

Take care of your skin and if in any doubt, please consult your doctor.

References

Phan K, Shumack S. Medicine Today. 2021;5:3-9
Marques E, Chen TM. Actinic keratosis. Treasure Island (FL): StatPearls Publishing. 2021
Dermatology Expert Group. Therapeutic guidelines 2022;eTG August 2022 edition.
Stockfleth E. et al J Eur Acad Dermatol Venereol.2017;31 Suppl 2:8-11
Chia A, et al. Australian Family Physician. 2007;36:539-541
Willenbrink TJ et al J Am Acad Dermatol. 2020;83:709-717
Stockfleth E, et al. Curr Ther Res Clin Exp. 2022;96:100661
Cornejo CM, et al. J Am Acad Dermatol. 2020;83:719-730.
Stockﬂeth E, et al. Dermatol Ther (Heidelb). 2022;12:467-479
Dohil MA. J Drugs Dermatol. 2016;15:1218-1224.
Sun safety | Cancer Council – Sun safety www.cancer.org.au/cancer-information/causes-and-prevention/sun-safety. Accessed February 2023.