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Actinic keratoses | Mate kiri hakihaki

Also known as solar keratoses

Key points about actinic keratoses

Actinic keratoses (mate kiri hakihaki) are scaly spots of sun damaged skin.
They usually happen in sun-exposed places – your face, ears, scalp, forehead, hands and legs.
Actinic keratoses are most common in people with fair skin or people who have worked outdoors.
If left untreated they can develop into a type of non-melanoma skin cancer called squamous cell carcinoma (SCC).

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One spot is called an actinic keratosis. If you have more than 1, they're called actinic keratoses.

Actinic keratoses start as flat pink or grey scaly spots. They're rough to touch and grow into patches and get thicker. They can then look white or yellow. There are often more than 1 of them, and they can grow to join together. Sometimes they can be tender (sore to touch.)

Actinic keratoses are very common in places that get a lot of sun exposure, especially:

the backs of your hands
ears
nose
cheeks
lips
temples
forehead
balding scalps.

Actinic keratoses are precancerous. That is, some can develop into a type of non-melanoma skin cancer called a squamous cell carcinoma. The risk is small, but if you have many this can add up.

The images below show actinic keratoses on the back of a hand and on a forehead.

Image credit: DermNet NZ

Actinic keratoses are skin damage caused by years of exposure to ultraviolet (UVB) radiation found in sunlight. They're more common if:

you have fair skin
you've been sunburned often in the past
you've worked outdoors for many years, especially without sun protection
your immune system is supressed by disease or medicines.

They often start to appear when you're in your 60s.

Diagnosis

Actinic keratoses have a typical appearance which can be diagnosed on examination by your healthcare provider. Sometimes they will use a dermoscope (a magnifying instrument). If they think you could have a squamous cell carcinoma (SCC) they might take a biopsy (a small sample to send to the laboratory). Read more about SCCs.

Treatment

The aim of treatment is to remove the abnormal skin cells to prevent them becoming skin cancers. New skin then forms from deeper cells that have escaped sun damage. You may choose to have them treated because of how they look or where they are. Actinic keratoses are usually treated by your GP or nurse.

Treatment will depend on the size and number of the skin lesions and may include:

Observation only.
Emollients (eg, 10% urea cream) for scaliness.
Cryotherapy – freezing with liquid nitrogen. This is a very common treatment that's easy to do. It may leave a pale scar and often needs repeating.
Topical creams – a range of creams are available. These are useful for treating areas that are not suitable for other treatments or for large areas where there are multiple keratoses, eg, on your scalp, forehead or ears. Examples of topical creams include 5-Fluorouracil cream and Imiquimod.
Photodynamic therapy (PDT) – this involves applying a photosensitiser (a porphyrin chemical) to the affected area before exposing it to a strong source of visible light. The treated area develops a 'burn' and then heals over a couple of weeks or so. Metvix PDT is available in Aotearoa New Zealand.
Excision – this involves a small surgical procedure using local anaesthetic to cut the lesion out. This will often need a few sutures (stitches), which are removed 5 to 14 days later (depending on the location).

If actinic keratoses are widespread, it may not be practical to treat all of them. In that case, your healthcare provider will focus on the most thickened, tender or annoying ones. The thicker and tender ones are at greatest risk of progressing to skin cancer.

Apps reviewed by Healthify

You may find it useful to look at some sun safety apps.

The best option for preventing actinic or solar keratoses from developing or getting worse is to protect your skin from the sun and UV rays.

Regularly check all your skin (from head to toe). If you see anything that is growing, bleeding or in any way changing, go and see your healthcare provider straight away.

Ways to protect your skin

Avoid outdoor activities when the sun is strongest – between 10am and 4pm from September to April in Aotearoa New Zealand.
Wear sunscreen and lip balm daily that offer SPF 30 or higher sun protection.
Use sunscreen that offers broad-spectrum (UVA/UVB) protection and is water resistant.
Apply the sunscreen and lip balm 20 minutes before going outdoors – make sure your skin is dry before applying sunscreen.
Apply the sunscreen to every part of your body that won't be covered by clothing. Reapply it every 2 hours if you're swimming or sweating.
Whenever possible, wear a wide-brimmed hat, long sleeves and long pants.
Wear sunglasses to protect the skin around your eyes.
Avoid getting a tan and never use a tanning bed or sun lamp.

Actinic keratoses are benign but can progress to invasive malignant disease if left untreated. Surgical excision is not routinely performed, due to the nature of the lesions. However, some actinic keratoses may be hypertrophic, in which case shave excision can be performed. Biopsy is not usually necessary for an isolated lesion of typical appearance, but should be considered for patients with recurrent lesions or if the diagnosis is unclear.

Treatment summary

Isolated scaly lesions – cryotherapy or surgical excision if the lesion is resistant to cryotherapy and hyperkeratotic.
Isolated flat lesions – imiquimod, fluorouracil (or ingenol gel).
Clustered lesions – cryotherapy initially to scaly lesions, followed by field treatment with imiquimod or fluorouracil (or ingenol gel or photodynamic therapy).
Atypical lesions with suspected malignancy – surgical excision.