Actinic (Solar) Keratosis


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 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. The presence of ten AK is associated with a 14% risk of developing an SCC within five years.  Evidence suggests the annual incidence of transformation from solar keratoses to squamous cell carcinoma is < 0.1%, and the risk of transformation is raised in immunocompromised patients



NOTE There is often a background of significant sun-damaged skin with pigment irregularity, telangiectasia, erythema and collagenosis (a yellow papularity of the skin)

The characteristic feature of actinic keratosis are multiple flat reddish brown lesions with a dry adherent scale:

  • The distribution of lesions will reflect the intensity of sun-exposure with the greatest number of lesions occurring on the head, neck, forearms and hands
  • Lesions usually take on a similar appearance and rarely exceed more than 1 cm in diameter
  • Rough surface scale - usually white, although in patients with skin type I AK are often more easily felt than seen
  • Often termed as flat, but some lesions can have significant amounts of scale (hypertrophic or Bowenoid AK)


When to refer

NOTE:  The majority of cases should be managed in primary care

Only refer to a specialist when:

  • the diagnosis is uncertain
  • lesions not responding to treatment outlined below
  • those patients with actinic damage who are at a much higher risk of developing an SCC, such as:
    • patients with history of immunosuppression e.g post renal transplant
    • very young patients presenting with AK – consider xeroderma pigmentosum


Refer urgently if any suspicion of malignancy

If required, seek advice via eRS on treatment for patients with more widespread / severe actinic damage


Patient information and advice

  1. Provide information of UV protection and also on actinic keratosis so they are aware of what to look out for
  2. Inform patients which skin changes need to be reported. Transformation into an SCC can be suggested by recent growth, discomfort, ulceration / bleeding. Patients also need to report any other skin lesions they are not familiar with
  3. Advice patients that once they start to develop AK they will almost certainly develop more. The aim of any treatment is to reduce the total number of AK on the skin at any one time
  4. Recommend the use of a moisturiser two to three times a day to help differentiate between early AK and dry scaly areas of normal skin



Consider the following treatment options:

  • Diclofenac sodium 3% (Solareze) bd for 3m. Optimum effect 1 m post treatment
  • Topical 5-Fluorouracil (Effudix) od –bd 3-4w. Ideal for widespread multiple ill defined solar keratoses. Spares normal skin so suitable for application to a wide skin surface. Patient must be warned about marked inflammation of skin which occurs prior to resolution
  • Ingenol mebutate gel (Picato). For face/scalp 150mcg/g gel applied once daily for three days. For trunk/extremities 500mcg/g gel applied once daily for two days
  • Cryotherapy. 10-15s freeze cycle. Ideal for isolated well-defined lesions


Click here for images

Advice and Guidance is being made available for all specialties, and is being provided by consultant specialists at East Kent Hospitals.  To make a request or to check to if a query has been answered, you will need to log in via the electronic Referral System (eRS)

Click here for the "how to access" e-Referral Advice and Guidance Manual for instructions on how to make a request and check responses

Have a question or query?

Get in touch