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Latest update 29/08/2010
This chaper is set out as follows:
Aetiology
- 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 AKs
- AKs are a consequence of cumulative long-term sun exposure and so the incidence increases with age
- The use of artificial UV radiation such as UVB and PUVA used to treatment psoriasis and a number of other skin conditions, as well as sun beds increase the risk
- Genetic factors play a role and individuals with fair skin, blue eyes and blond hair are at higher risk
- Men are more affected than women
- Patients with Xeroderma Pigmentosum or Albinism can develop lesions at a very young age
- AKs can occasionally transform into squamous cell carcinoma (SCC) - the presence of ten AKs is associated with a 14% risk of developing an invasive SCC within 5 years
Key diagnostic features
- Distribution - reflects the intensity of sun exposure with the greatest number of lesions occurring on the head, neck, forearms and hands
- There is often a background of significant sun-damaged skin with pigment irregularity, telangiectasia, erythema and collagenosis (a yellow papularity of the skin)
- Morphology
- Seldom exceed more than 1cm in diameter
- Rough surface scale - usually white
- Often termed as flat, but some lesions can have significant amounts of scale (hypertrophic or Bowenoid AKs)
- There exists a number of variants
- Erythematous (the rough scale is more palpable than visible)
- Pigmented
- Hypertrophic / Bowenoid (thick areas of scale)
- Cutaneous horn: a horny protuberance, the majority are caused by AKs or warts but 15% are secondary to an underlying SCC - please refer to the chapter on cutaneous horns
- Lichenoid (smooth and shiny, mainly occurring in areas of friction)
- Actinic chelitis (lips)
Who should manage actinic keratoses?
Given the very large numbers of patients who have AKs it is important that the majority should be managed in the community, and preferably by GPs otherwise consultant and GPwSI clinics will become overburdened, and patients with more serious skin problems will wait longer to be seen by a specialist
Who should be referred?
- Where there is diagnostic uncertainty - refer to a GPwSI or consultant dermatologist
- If the lesion is suspicous of an SCC refer to secondary care as a two-week wait (the majority should be referred to dermatology, although if very suspicious for an SCC consider referral to plastic surgery - check local guidelines). The following could suggest transformation from an AK into an SCC
- Recent growth / tenderness / inflammation
- If the lesion is elevated or indurated. Thickened areas of surface scale should be removed if present as they may obscure the lesion
- Bleeding / ulceration
- Beware lesions on lips - SCC can be very subtle at this site
- The following patients with AKs should be referred to dermatology as their risks of developing an SCC are much greater
- Immuno-suppressed patients, in particular post transplant
- AKs induced by phototherapy used for treating other conditions e.g. PUVA for psoriasis
- Very young patients presenting with AK – consider Xeroderma Pigmentosum
Management
General measures - appropriate for all patients
- Provide a patient information leaflet
- General skin examination to look for other significant skin lesions
- Sun protection - up to 25% of AKs will resolve if patients adhere to advice
- Vitamin D - patients limiting their recreational sunlight exposure need to have an adequate dietary intake of vitamin D
- Moisturisers - it can sometimes be difficult to differentiate between early actinic keratoses and dry scaly areas of normal skin. The use of a moisturiser 2-3 times a day can be helpful in differentiating between areas of normal and abnormal skin
- Patient expectation - once patients start to develop AKs they will almost certainly develop more. The aim of any treatment is to reduce the total number of AKs on the skin at any one time
- Education - 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
Observation
- Not all patients need treating e.g. patients with smaller numbers of lesions, especially if they have a reduced life expectancy - such patients should be given a choice or whether or not they wish to have their lesions treated
A few lesions or larger numbers that are widely distributed (i.e. dotted around the face, scalp and hands etc)
- Treat the individual lesions and not the normal surrounding skin
- Cryotherapy - a single freeze-thaw cycle of approximatley ten seconds (avoid the gaiter are of the legs due to risk of leg ulceration)
- Efudix ® cream (5-FU) - apply every night for four weeks. Wash hands thoroughly after application. Leave treated areas uncovered and wash off the following morning. Patients should be advised to expect a relatively mild degree of redness and discomfort during the treatment period
Field change
Field change refers to areas of skin that have multiple AKs associated with a background of erythema, telangiectasia and other changes seen in sun-damaged skin. These areas are more at risk of developing SCC, especially if left untreated and as such it is recommened that they should be treated more vigorously. As such the teatments used should be applied to the whole area of field damage and not just the individual lesions
As when treating other patients with actinic keratoses the primary aim of treatment is to reduce the total number of lesions that the patient has at any one time, the fewer lesions a patient has the less risk they have for developing an SCC. Treatment courses will need to be repeated from time to time
Patients should be given a choice of treatments that broadly fit into the following groups:
I) Efudix ® cream (5-FU) or Aldara ® cream (5% imiquimod cream)
- Advantages - more effective and so patients will have fewer lesions at any one time. Shorter treatment courses (4 weeks)
- Disadvantages - more adverse effects in the skin and so treatment courses should be planned away from holidays etc
II) Solaraze ® gel (3% diclofenac in sodium hyaluronate)
- Advantages - generally less adverse effects
- Disadvantages - most specialists feel it is less effective and so patients will have more lesions at any one time. Treatment courses longer (12 weeks)
III) Other treatment options
- 'Top-ups' - liquid nitrogen can be used in addition to any of the treatments referred to above
- Photodynamic therapy (PDT) - can be used to treat areas of field damage. This is provided by some dermatology departments and occasionally GPwSI clinics
Notes on indiviual treatments when used to treat field damage
Aldara
- Use overnight three times a week (e.g. Mon, Wed, Friday) for 4 weeks. Wash the treated area the following morning
- It is supplied in boxes of 12 sachets. One sachet will cover most areas of focal damage e.g. the back of a hand or a forehead if applied thinly, but it will not cover larger areas such as the top of the scalp
& lt;li>Patients should be warned that they are likely to develop marked but tolerable erythema and crusting of the skin. A few patients develop an intense local reaction with significant discomfort and flu-like symptoms and stop treatment. Patients can be reassured that the skin will settle down quickly
- Patients should be reviewed after 3 months
- Evidence from small studies has shown that Aldara is the most effective treatment in that patients have fewer lesions 12 months after the treatment has been completed
Efudix
- Use every night for 4 weeks
- It should be applied with a gloved finger, if not wash the finger after application. The treated area needs to be washed the following morning
- Patients should be warned to expect marked erythema with crusting of the skin. Levels of discomfort may be greater than with Aldara
- The advantage of Efudix is that it comes in a 40 gram tube and so treatment can cover a larger area. However when used on a larger area e.g. the top of the scalp, it is often poorly tolerated and in such circumstances consider using Efudix 2-3 nights a week in the first instance and asking the patient to gradually increase the frequency if needed until an erythematous reaction occurs. Once erythema has developed the patient should continue on for 4 weeks at a frequency of application that they can tolerate
- Patients should be reviewed after 3 months
Solaraze
- Although the evidence base for the treatment of AKs is poor, most dermatologists view Solaraze as being less effective than the other treatments, however it is generally associated with fewer adverse effects. As such it can be considered for use when the degree of skin damage is milder or in patients less likely to tolerate the treatments referred to above
- As with other treatments it is possible to combine liquid nitrogen with Solaraze, and use the liquid nitrogen on those AKs that do not respond to the Solaraze
- Solaraze needs to be used twice a day for 12 weeks and the patient followed up at 16 weeks to assess response
Please click on the following link - 'Guidelines for the Management of Actinic Keratoses' for more in-depth guidelines
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Figure 1 - AK
The features of a classical AK - a flat lesion with white rough surface scale |
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Figure 2 - AK right helix
The scale was removed to reveal a flat red area underneath
The lesion was treated with 10 seconds of liquid nitrogen given via a cryogun
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Figure 3 - Field change with multiple AKs on a background of sun-damaged skin
Such patients have extensive changes with clinical features of AK (black lines) and sub-clinical areas shown up as red patchy areas (red lines)
This patient was treated with Aldara applied to the whole area three nights a week for 4 weeks
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Figure 4 - Field change on the anterior scalp
The area highlighted (black arrow) was treated with PDT but it could equally have been treated with Aldara or Efudix
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Figure 5 - Extensive field change
An area this size is likely to be too extensive for Aldara or PDT
Efudix would be the preferred treatment option but consideration should be given to starting it at a reduced frequency of 2-3 nights a week
If the patient was not keen on using Efudix another option would be to use Solaraze gel on the whole area and then use liquid nitrogen on any remaining AKs
Patients with this degree of damage are best managed by a GPwSI or a dermatologist
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Figure 6 – Multiple AK of the feet
Indiviudal lesions suitable for Efudix cream OD for 4 weeks. Cryotherapy could also be considered in the absence of vascular insufficiency
Liquid nitrogen should be avoided around the gaiter areas of the legs and ankles due to the risk of leg ulceration
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Figure 7 – Pigmented AK
The lesion was rough on palpation
The treatment given was 10 seconds of cryotherapy via a cryogun. The eye was protected
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Figure 8 - Dermoscopic appearance of an AK
Lesions have a strawberry-like appearance |
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Figure 9 – Lichenoid AK
Lesions in areas of friction loose there scale |
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Figure 10– Pigmented AK shin
A biopsy was needed as the differential inculded Bowen's disease, a superficial BCC and even a superficial spreading melanoma
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Figure 11 – Cutaneous Horn arising from an AK
Base of lesion not indurated. Histology following curettage confirmed the diagnosis |
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Figure 12 – Cutaneous Horn arising from SCC
The red frim nodule at the base (black line) increased the level of suspicion |
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Figure 13 – SCC arising from an AK
This lesion suddenly increased in size, the scale was picked off to reveal a slightly raised base |
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