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Q&A: Actinic keratoses

Nearly a quarter of the UK population aged 60 years and over have actinic keratoses, according to NICE – but what are they? Are they cancerous and how should they be treated?

Q: What are actinic keratoses (AKs)?

A: Actinic keratoses (also known as solar keratoses) are scaly or hyperkeratotic skin lesions, usually less than 1cm in diameter and associated with long-term sun exposure. 

They are more common in older people and in areas that are usually exposed, such as the scalp (especially in balding men), face, forearms and hands. Skin types I and II (blonde, blue eyes, fair skin) are at higher risk. Artificial UV radiation (e.g. sunbeds) increases the risk. 

Actinic keratoses in young people are very rare and may be due to xeroderma pigmentosum (a hereditary condition characterised by extreme sun sensitivity).

Q. Are AKs pre-cancerous?

A: The presence of 10 AKs is associated with a 14 per cent risk of developing a squamous cell carcinoma (SCC) within five years, according to the Primary Care Dermatology Society – but there is no way of knowing which ones will progress. AKs are normally asymptomatic; recent growth, tenderness, bleeding or ulceration suggest transformation into a SCC and warrant priority referral to secondary care (two-week wait).

Q. What is field change and why does it matter?

A: Field change describes areas of skin that have multiple AKs on a background of red, thinning skin as a result of long-term sun exposure. It occurs on sun-exposed areas (e.g. balding scalps, forearms). Such areas are thought to be at greater risk of developing SCC, especially if left untreated. 

Q. Can AKs be prevented?

A: AKs can only be prevented by avoiding exposure of skin to sunlight as much as possible. In practice this would mean keeping the skin covered and/or using factor 50 sunscreen on all exposed skin, even when the sun is not shining. 

Q. Are AKs the same as seborrhoeic keratoses?

A: Seborrhoeic keratoses (also known as seborrhoeic warts or basal cell papillomas) are thickened, often pigmented lesions with a characteristic ‘stuck on’ appearance. People often have multiple lesions and they can be confused with melanoma. They are essentially benign and do not require treatment unless they are in an inconvenient place (e.g. catching on clothing). 

Q. What is the link between AKs and immunosuppression? 

A: People who are immunosuppressed – for example, organ transplant recipients who are taking immunosuppressant drugs – are more likely to develop SCC. They need to keep all exposed skin protected with factor 50 sunscreen to minimise the risk.

Q. How should AKs be managed?

A: Many AKs do not require any treatment. It is worth remembering that up to 25 per cent of AKs resolve spontaneously without treatment. The use of topical emollients and advice on sun protection may be sufficient. Some patients are at higher risk of developing a SCC, including those who are immunosuppressed and people with: 

  • A history of skin cancer
  • Extensive sun damage
  • Previous phototherapy (UVB or PUVA)
  • Diagnosis of xeroderma pigmentosum
  • Periocular AK
  • Previous failure to respond to first-line therapy.

The primary aim of treatment is to reduce the total number of AKs and thereby reduce the risk of developing a SCC. AKs are normally managed in primary care by a clinician with appropriate skills. The choice of treatment depends on the number, size, duration and location of lesions, patient preferences and likely cosmetic outcome. 

Q. What treatments are available?

A: Low grade, solitary lesions are treated individually, avoiding the surrounding skin. The options are: fluorouracil 5% cream, fluorouracil 0.5% & salicylic acid 10% (Aktikerall), tirbanibulin cream (Klisyri) or cryotherapy (see table). Local prescribing restrictions may apply. 

Where there is field change (multiple AKs with background erythema), the risk of developing SCC is believed to be greater so the whole area is treated. The options include imiquimod (Aldara or Zyclara), fluorouracil 5% cream and diclofenac sodium 3% in sodium hyaluronate (see table). A recent study suggested that twice daily 5% fluorouracil cream was the most effective and least expensive. Photodynamic therapy may be available in some centres. Treatments may need to be repeated in the future if/when more AKs appear.

Q. What do people need to know about AK treatments?

A: Patients need to be warned that all treatments for AKs cause local skin reactions including moderate-severe redness, soreness, inflammation and crusting – it will almost certainly look worse before it gets better. These effects can last for a few weeks (even if the application time itself is short) and can be distressing. They are the effects of the treatment and show that it is having the desired action. Treatment should be discontinued if reactions are intolerable. 

Patients may wish to avoid starting treatment when important social events are coming up (e.g. to avoid having unsightly lesions in wedding photos). Moreover, patients who have had a bad experience with a treatment may be reluctant to use it again in the future.

Treatments for actinic keratoses seen in primary care



Treatment schedule



Dry skin. No limits

Whenever skin is dry

Humectant-containing (urea or glycerine) preferred

Sunscreen – SPF 50

All exposed skin

During UV exposure

Broad spectrum preferred

5-fluorouracil cream 5% (Efudix)

Up to 500cm2

Nightly for 4 weeks

Tirbanibulin cream (Klisyri)

Up to 25cm2

Daily for 5 days

Black triangle!

5-fluorouracil 0.5% & 10% salicylic acid (Aktikerall)

Up to 25cm2

Daily, 6-12 weeks

5-FU concentration low – may be less irritant


Individual lesions

Single freeze-thaw cycle

Can cause swelling, ulceration, residual hypopigmentation

For field change: All of the above except cryotherapy or:

5% imiquimod cream (Aldara)

3 nights a week
for 4 weeks

Marked erythema can occur

Photodynamic therapy (PDT)

Smaller areas of field change

Single treatment

Only available in some centres. Skin settles quickly. Cosmetic results good

For larger areas of field change:

3% diclofenac gel

Twice daily for
8-12 weeks

Well tolerated. Best for thin lesions

3.75% imiquimod cream (Zyclara)

Up to 25cm2

Daily for 2 weeks. Repeat
after a 2-week gap

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