Actinic keratosis


  • Actinic keratosis should be treated to avoid the risk of cancerous development and the aesthetic harm.
  • Cryotherapy with liquid nitrogen and photodynamic therapy can be used at dermatological outpatient clinics.
  • Imiquimod and diclofenac gel can be used also by a primary care physician. However, the use of imiquimod requires good acquaintance with the drug because it causes a strong local reaction.


  • Also known by the name solar keratosis
  • A degenerative disorder of epidermal cell growth; a precancerous lesion that can develop into an epidermoid carcinoma that does not (yet) infiltrate through the basal membrane.
  • Actinic keratosis can be treated without affecting the dermis (i.e. without causing a scar).


  • Common among those with fair skin. Occurs in old age on sun-exposed areas of the skin.
  • The face, bald scalp, upper corners of the ear lobes, and dorsum of the hand are sites of predilection.


  • An erythematous, asymptomatic, well-demarcated small plaque is the first manifestation .
  • The plaque grows up to a diameter of a few centimetres, scales, and may develop thick hyperkeratosis, even a cornu cutaneum.
  • In most cases there are multiple lesions.
  • Take a biopsy or refer the patient to a dermatologist.

Treatment and prophylaxis

  • Before treatment exclude an epidermoid carcinoma (1).
  • Cryotherapy with liquid nitrogen is effective, cheap, and the aesthetic outcome is good . Best suited for solitary localized keratoses.
  • Excision is seldom needed; the cosmetic result is better with cryotherapy.
  • Topical treatments are suitable particularly for actinic keratosis occurring in large areas (so-called field cancerization).
  • Topical treatments induce a skin irritation reaction, the strength of which is individual. It is important to inform the patient about this.
  • Primary topical treatments
    • Imiquimod 5% and 3.75% cream
    • Ingenol mebutate gel
  • Secondary topical treatments
    • Diclofenac 3% gel. Diclofenac can well be used for thin lesions, but the gel should be applied twice daily for 3 months before more permanent treatment results can be expected.
  • Tretinoin cream (0.05%) can be used for the treatment and prophylaxis of very thin lesions [Evidence Level: C]. The cream can be used for long periods, even continuously.
  • Photodynamic therapy [Evidence Level: B] (PDT) or the so-called daylight PDT are used in many dermatological outpatient clinics.
  • Topical treatments can also be combined with cryotherapy or photodynamic therapy.
  • Sunscreen preparations slow the development of new lesions [Evidence Level: B].
  • Assess healing after 2–3 months.

Evidence Summaries


  • In following years new lesions will probably appear.
  • If left untreated for years, actinic keratosis may develop into an epidermoid carcinoma.

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