Actinic Keratosis Flashcards
What is actinic keratosis?
Actinic keratosis is a precancerous scaly spot found on sun-damaged skin, also known as solar keratosis. It may be considered an early form of cutaneous squamous cell carcinoma (a keratinocyte cancer).
What causes actinic keratosis?
Actinic keratoses are the result of abnormal skin cell development due to DNA damage by short wavelength UVB.
They are more likely to appear if the immune function is poor, due to ageing, recent sun exposure, predisposing disease, or certain drugs.
What are the risk factors for actinic keratosis?
Actinic keratoses affect people that have often lived in the tropics or subtropics and have predisposing factors such as:
- Other signs of photoageing skin
- Fair skin with a history of sunburn
- History of long hours spent outdoors for work or recreation
- Defective immune system
What are the clincial features of actinic keratosis?
Actinic keratosis may be solitary but there are often multiple keratoses. The appearance varies.
- A flat or thickened papule, or plaque
- White or yellow; scaly, warty, or horny surface
- Skin coloured, red, or pigmented
- Tender or asymptomatic
Where does actinic keratosis commonly affect?
Actinic keratoses are very common on sites repeatedly exposed to the sun, especially the backs of the hands and the face, most often affecting the ears, nose, cheeks, upper lip, vermilion of the lower lip, temples, forehead, and balding scalp. In severely chronically sun-damaged individuals, they may also be found on the upper trunk, upper and lower limbs, and dorsum of feet.
What are the complications of actinic keratosis?
The main concern is that actinic keratoses indicate an increased risk of developing cutaneous squamous cell carcinoma.
Cutaneous horn may arise from an underlying actinic keratosis or SCC.
Because they are sun damaged, people with actinic keratoses are also at risk of developing actinic cheilitis, basal cell carcinoma (BCC, which is more common than SCC), melanoma, and rare forms of skin cancer such as Merkel cell carcinoma.
What is the risk of developing SCC from actinic keratosis?
It is rare for a solitary actinic keratosis to evolve to squamous cell carcinoma (SCC), but the risk of SCC occurring at some stage in a patient with more than 10 actinic keratoses is thought to be about 10 to 15%. A tender, thickened, ulcerated, or enlarging actinic keratosis is suspicious of evolution to SCC.
How is actinic keratosis diagnosed?
Actinic keratosis is usually easy to diagnose clinically or by dermoscopy. Occasionally, a biopsy is necessary, for example, to exclude SCC, or if treatment fails.
Briefly describe the treatment of actinic keratosis
Actinic keratoses are usually removed because they are unsightly or uncomfortable, or because of the risk that skin cancer may developin them.
Treatment of an actinic keratosis requires removal of the defective skin cells. Epidermis regenerates from surrounding or follicularkeratinocytes that have escaped sun damage.
Tender, thickened, ulcerated, or enlarging actinic keratoses should be treated aggressively. Asymptomatic flat keratoses may not require active treatment but should be kept under observation.
Briefly describe the physical treatments for actinic keratosis
Physical treatments are used to destroy individual keratoses that are generally symptomatic or have a thick hard surface scale. The lesions may recur in time, in which case they may be retreated by the same or a different method.
Treatments:
- Cryotherapy using liquid nitrogen
- Shave, curettage and electrocautery
- Excision
Briefly describe the field treatments of actinic keratosis
Creams are used to treat areas of sun damage and flat actinic keratoses, sometimes after physical treatments have been carried out. Field treatments are most effective on facial skin. Pretreatment with keratolytics (such as urea cream, salicylic acid ointment or topicalretinoid), and thorough skin cleansing improves response rates. Results are variable and the course of treatment may need repeating from time to time.
Treatments:
- Diclofenac
- 5-Fluorouracil
- Imiquimod cream
- Photodynamic therapy
What are the side effects of field treatments for actinic keratosis?
With the exception of diclofenac gel, field treatments all result in local inflammatory reactions such as redness, blistering and discomfort for a varying length of time.
How can actinic keratosis be prevented?
Actinic keratoses are prevented by strict sun protection. If already present, actinic keratoses may improve with a very high sun protection factor (50+) broad-spectrum sunscreen applied at least daily to affected areas, year-round.
The number and severity of actinic keratoses can also be reduced by taking nicotinamide (vitamin B3) 500 mg twice daily.
What is the prognosis of actinic keratosis?
Actinic keratoses may recur months or years after treatment. The same treatment can be repeated or another method used. Patients who have been treated for actinic keratoses are at risk of developing new keratoses. They are also at increased risk of other skin cancers, especially intraepidermal squamous cell carcinoma, invasive cutaneous squamous cell carcinoma, basal cell carcinoma and melanoma.
What is shown in the image?
Actinic Keratosis
What is shown in the image?
Actinic Keratosis
What is shown in the image?
Actinic Keratosis
What is shown in the image?
Actinic Keratosis
