Actinic Keratosis (Solar Keratosis)

Home » Skin Cancer » Actinic Keratosis (Solar Keratosis)

Actinic Keratosis is a precancerous skin condition, mainly towards a type of cancer called Squamous Cell Carcinoma (SCC).

It is of course also a marker of heavy sun damage – and heavy sun exposure and damage increase our risk of all skin cancers including melanoma. The risk of individual AK lesions becoming an SCC is quite low – it is estimated from Australian studies that each lesion has a 0.1% chance of becoming an SCC every year. American research suggests a risk of around 0.6% – still very low. However, when we have tens or sometimes hundreds of lesions this increases our risk.


The most important ‘treatment’ is to protect your skin from the sun. The best sunscreen is a roof or direct shade. The second best sunscreen are large hats (eg the Akubra). Remember baseball caps expose the ears. We recommend constant sunscreen use but emphasise sunscreen alone will not adequately protect us from skin cancer (and is often not used properly). For more information on sunscreen please read the page “Everything you need to know about sunscreen”/

Sunscreen – use SPF 50+ and apply it thickly. See the below from the Cancer council of Australia;

“For an adult, the recommended application is 5ml (approximately one teaspoon) for each arm, leg, body front, body back, and face (including neck and ears). That equates to a total of 35ml (approximately seven teaspoons) for a full-body application.

Sunscreen should always be reapplied at least every two hours, irrespective of the water resistance of the sunscreen. Swimming, sport, sweating, and towel drying can reduce the effectiveness of the product, so sunscreen should always be reapplied after these activities.”

Sunscreen should be worn (in addition to all other protections above) every day that the UV index is 3 or greater.


The following list is a guide only and you should talk to your treating doctor for advice specific to you. Treatment of Actinic Keratosis is to try to reduce your risk of developing skin cancer, to make it easier for your doctor to see early cancers (which can be otherwise concealed in a sea of bad pre-cancerous change), and for cosmetic reasons (treatment of AK will make your skin look better usually).

We divide AK treatment into “spot treatments” and “field treatments”. Field treatments can also be used for individual lesions if desired.

Spot treatments – Laser and Cryotherapy

When we have small areas of well-defined AK sometimes a doctor will recommend treatment to individual spots. We call this spot treatment. We have two types of spot treatment – Cryotherapy and Laser.

Cryotherapy is cheap and effective when performed properly. When used aggressively it has cure rates of 67-99% (excluding the arms or hands). The problem with cryotherapy is when used properly it can cause permanent areas of hypopigmentation (white spots) or hyperpigmentation (brown spots) – this is because the pigment cells are more sensitive to the cold than the pre-cancerous cells. It is for this reason that our doctors generally do not use cryotherapy, and especially not on the face.

Laser has been used to treat AK for decades. It is effective with less chance of pigmentation change compared to cryotherapy.

Field treatments

Field treatments treat entire areas (eg the scalp, the forehead, the hands), not just specific precancerous lesions. This makes sense because the skin around AK has been exposed just as much to the sun as the skin that has developed the AK – and often there are early areas of precancerous change within normal-appearing skin – even if appearing normal under the microscope. The drawback is that these treatments are more painful and often take longer. Efudix, Picato, and PDT all have similar effectiveness of around 80% clearance of AK. Field treatments carry a small risk of permanent pigmentation changes in some areas – darker or lighter spots. Talk to your doctor.

We tend to recommend Daylight Photodynamic Therapy (PDT) for the treatment of facial and scalp Actinic Keratosis because it is the most convenient, least painful with the shortest downtime.

Daylight PDT is a once off treatment performed at the clinic. Sometimes if the skin is quite rough your doctor may prescribe a cream to make it smoother prior to treatment.

On the day the skin is cleansed, then the nurse first applies a SPF 50+ sun screen. This sounds odd but the cream is activated by visible light not harmful UV rays. We do not want UV damaging the skin. We allow 15 minutes for the sunscreen to absorb. Then we remove any scale and crust still present on individual lesions to allow optimal penetration for the metvix treatment. Metvix (the Daylight PDT cream) is then applied to the treatment area.

The patient is then sent outside for daylight exposure. Length of exposure depends on variables that the doctor will discuss with you but usually between 2-4 hours. After the daylight exposure patients are given a “take home pack” to remove any remaining cream on the face.

Efudix (5-Fluorouracil) is a cream applied twice a day to areas (eg. the forehead, cheeks, nose, tops of ears, back of hands). Your doctor will tell you how long you use it for, but generally 3-6 weeks depending on why you are using it.

Picato (Ingenol mebutate) is a newer cream developed in Australia. We use it similar to efudix, but the treatment times are much shorter (once a day for either 2 or 3 days depending on where you are using it). The reactions tend to be more severe than efudix, including blistering. 

Aldara (Imiquimod) is one of the oldest creams and also one of the most effective. A total face treatment would take over a year. Shorter treatment regimes exist but they may be less effective than the creams described above.

Solaraze (Diclofenac) is a cream applied twice a day for 2-3 months. It has the advantage of being the least inflammation inducing (ie. not as red and painful as the others) but it is also the least effective.

How long will it take for the redness to go away?

Everyone is different and the amount of redness and pain is in general proportional to the amount and severity of precancerous change. Below is only a guide and you should discuss specifics with your treating doctor.

In general the peak redness and pain occur around day 3 of all treatments except efudix which tends to continue to peak until application is ceased.

  • Laser: 7 days
  • Daylight PDT: 7-10 days
  • Picato: 2 weeks
  • Efudix: 2 weeks after treatment has finished (ie 5 – 8 weeks depending on treatment length)
A spot of Solar Keratosis on skin