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This guideline has been developed by the Primary Care Dermatology Society. A grant was obtained from Leo Pharma to cover the costs of the honoraria, meeting, and venue. Leo Pharma was not involved in the development of the guideline.


"An actinic keratosis (AK) is a common sun-induced scaly or hyperkeratotic lesion, which has the potential to become malignant. NICE estimates that over 23% of the UK population aged 60 and above have an AK. Although the risk of an AK transforming into a squamous cell carcinoma (SCC) is very low, this risk increases over time and with larger numbers of lesions


  • Men are more affected than women
  • AKs are a consequence of cumulative long-term sun-exposure and so the incidence increases with age
  • Artificial ultraviolet (UV) radiation—such as UVB and psoralen combined with UVA (PUVA), which is used to treat psoriasis and a number of other skin conditions—and the use of sun beds increase the risk
  • Genetic factors play a role and individuals with fair skin, blue eyes, and blonde hair are at higher risk


  • Lesions occur on sun-exposed areas, i.e. the head, neck, forearms, and hands:
    • usually less than 1 cm in diameter
    • rough surface scale—usually white
  • Most are flat, but some lesions can have significant amounts of scale (hypertrophic or Bowenoid AK)
  • The majority of cutaneous horns are caused by AKs or warts, but 15% are secondary to an underlying SCC
  • General measures
    1. Applicable to all patients and may be all that is needed for management: AKs are a marker of UV damage: examine other areas of the skin
    2. Encourage prevention: sun screen and protection
    3. Advise patients to report change
    4. Consider use of emollients for symptom control

Clinical grading

Grade I

  • Flat, pink maculae without signs of hyperkeratosis and erythema, often easier felt than seen. Scale and possible pigmentation may be present

Grade II

  • Moderately thick hyperkeratosis on background of erythema that are easily felt and seen

Grade III

  • Very thick hyperkeratosis, or obvious AK; differential diagnosis includes thick intra-epidermal carcinoma or SCC

Field damage

  • Large areas of multiple AKs on a background of erythema and sun damage

Indications for referral

  • The majority of AKs should be managed in primary care (as set out in the NICE guidance) but the following should be referred to a specialist:
    • if the lesion is suspicious of an SCC refer to secondary care under the 2 week rule. The following could suggest transformation from an AK into an SCC:
      • recent growth/tenderness/inflammation
      • a nodular lesion
      • bleeding/ulceration and lesions on lips
    • diagnostic uncertainty
    • patients with more widespread/severe actinic damage
    • immunosuppressed patients, in particular post-transplant
    • very young patients presenting with AK—consider xeroderma pigmentosum
Suggested treatment regimens
Generic nameProtocolNotes
3% diclofenac with 2.5% hyaluronic acid Twice daily for 60–90 days Because of the length of treatment needed, compliance may be an issue
5% fluorouracil (5-FU) Once or twice daily for 3–4 weeks Early and severe inflammatory reaction is normal, typically peaking in the second week
0.5% 5-FU+10% salicylic acid Once daily for 6–12 weeks Apply with brush applicator and peel off existing coating before reapplication
5% imiquimod Apply three times a week for 4 weeks. Assess after 4-week interval. Repeat if required Flu-like symptoms are occasionally reported
3.75% imiquimod Two treatment cycles of 2 weeks, separated by 2 treatment free weeks Flu-like symptoms are occasionally reported
0.015% ingenol mebutate—face and scalp Once daily for 3 consecutive days Skin reaction may occur from day 1 and usually resolves within 2 weeks
0.05% ingenol mebutate—trunk and extremities Once daily for 2 consecutive days Skin reaction may occur from day 1 and usually resolves within 4 weeks

Primary care treatment pathway

  • Many patients will only need a diagnosis and explanation with advice regarding sun exposure limitation and sunscreens, use of emollients for symptomatic relief, and warning of what to look out for if lesions change
  • All topical treatments cause inflammation, which indicates their desired action against abnormal cells. If severe, the treatments should be stopped until the reaction subsides and then restarted, perhaps at a reduced frequency:
    • patients should be warned to expect this effect of the treatment rather than to regard it as an unwanted side-effect. Written advice is essential and nurse support is beneficial to help patients through the inflammatory phase
  • Complete clearance of lesions can be delayed several weeks beyond completion of topical therapies
  • For more symptomatic lesions, specific treatment may be indicated as in the AK pathway
  • Leaflets regarding UV exposure and skin cancer awareness, and recommended regimens for treatment can be downloaded from the PCDS website at www.pcds.org.uk
Primary care treatment pathway of actinic keratosis

full guidelines available from…
Primary Care Dermatology Society, PO Box 789, Rickmansworth, WD3 0NU (Tel—0333 939 0126)

Primary Care Dermatology Society. Actinic (Solar) Keratosis primary care treatment pathway. September 2012, updated April 2014.
First included: June 2013, updated June 2014