Actinic keratosis
See also in: External and Internal Eye,Hair and ScalpAlerts and Notices
Synopsis
The frequency of AKs increases with age and cumulative lifetime sun exposure. They are also more common in individuals who are immunosuppressed (especially after solid organ transplantation) and in males. They may resolve with protection from ultraviolet (UV) light. Some medications (ie, capecitabine, sorafenib) may induce inflammation of existing AKs.
Patients with AKs are at higher risk for developing nonmelanoma skin cancer. AKs have the potential to evolve into squamous cell carcinoma (SCC). It is estimated that the likelihood that a given AK will evolve into an invasive SCC is approximately 0.075%-0.096% per lesion.
The term "field cancerization" is used to describe areas of skin at risk for both AK and SCC. Clinically, this manifests as numerous AKs and squamous cell carcinoma in situ (SCCis) with or without invasive SCCs in a field of chronically sun-damaged skin. Risk factors include male sex, lighter skin color, older age, underlying immunosuppression, and the degree of prior exposure to UV light.
Related topic: actinic cheilitis
Codes
ICD10CM:L57.0 – Actinic keratosis
SNOMEDCT:
201101007 – Actinic keratosis
Look For
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Superficial basal cell carcinoma
- SCCis (Bowen disease)
- Psoriasis
- Flat wart
- Common wart
- Seborrheic dermatitis – Patients with significant seborrheic dermatitis will benefit from initial treatment of dermatitis before beginning treatment for AK.
- SCC
- Seborrheic keratosis
- Discoid lupus erythematosus
- Disseminated superficial actinic porokeratosis
- Severe xerosis – Wiping the skin with water or an alcohol pad will minimize background xerosis. In addition, xerosis lacks the classic gritty sensation on light palpation.
- Lentigo (pigmented variant)
- Lentigo maligna (pigmented variant)
Best Tests
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Management Pearls
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Therapy
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Drug Reaction Data
Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.Subscription Required
References
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Last Reviewed:12/18/2021
Last Updated:02/10/2022
Last Updated:02/10/2022
Patient Information for Actinic keratosis
Overview
Actinic keratoses, also known as solar keratoses, are small rough or scaly areas of skin due to damage from sun exposure. Some actinic keratoses can turn into squamous cell skin cancer, so it is important to perform self-examinations often and catch them early.Who’s At Risk
People with light skin colors who sunburn easily; have trouble tanning; have blue, green, or hazel eyes; and red or blond hair are most at risk for developing actinic keratoses. Those who have had a lot of sun exposure in their youth are at a high risk as well. Those with a weak immune system due to chemotherapy, HIV, or an organ transplant are at higher risk.Spots usually appear in those who are older (over 50), but they can start appearing in younger adults who have had a lot of sun exposure. Darker-skinned individuals are rarely affected.
Signs & Symptoms
The sun-exposed areas of the face, scalp (where balding), ears, neck, forearms, and backs of the hands are most commonly affected with actinic keratoses, but any skin area frequently exposed to sun can be involved.Patches are usually less than an inch in size with slight scale (sometimes thick like a wart) and a pink, red, or brownish color. They are slightly rough to the touch, like fine sandpaper, and may be a bit sensitive.
- Mild - one or two spots, not thick or hard
- Moderate - scattered, few spots
- Severe - numerous or thick, hard, or bleeding spots
Self-Care Guidelines
Prevention is very important. Sun protection can reduce the number of new areas occurring and may help small lesions go away on their own.- Avoid direct sun in the middle of the day (10 AM to 3 PM). Remember: snow and water reflect light to the skin, and clouds still let a lot of light through, so you may still be exposed to ultraviolet light even on cloudy days.
- Use a hat with a wide brim. A baseball hat does not give much protection.
- Cover up with tightly woven clothing. Some manufacturers make specialty clothing with a high sun protection factor (SPF) rating, or you can purchase a special ingredient to be added to your washer that can "wash" SPF into your clothing.
- Use sunscreen on all exposed skin areas, including the lips, before going outdoors. A broad spectrum (blocks UVB and UVA light), with an SPF of at least 30, is best. Apply generously 30 minutes before going outdoors and reapply every 2 hours or after swimming or sweating a lot.
- Do not use tanning beds!
- A low-fat diet (less than 21% calories from fat) has been shown to reduce the incidence of actinic keratoses.
- In front of a full-length mirror, inspect the front of your body making sure to look at the front of your neck, chest (including under breasts), legs, and genitals.
- With your arms raised, inspect both sides of your body making sure to examine your underarms.
- With your elbows bent, examine the front and back of your arms as well as your elbows, hands, fingers, area between your fingers, and fingernails.
- Inspect the tops and bottoms of your feet, the area between your toes, and toenails.
- With your back to the mirror and holding a hand mirror, inspect the back of your body, including the back of your neck, shoulders, legs, and buttocks.
- Using a hand mirror, examine your scalp and face.
When to Seek Medical Care
If you have severe changes or have a spot that is growing or bleeding, see the doctor. Sometimes a biopsy may be done to look for skin cancer.Treatments
- Local destruction with freezing (cryosurgery), scraping (curettage), burning (electrocautery), dermabrasion, or a laser
- Creams with either tretinoin, adapalene, fluorouracil, diclofenac, or imiquimod
- Chemical peeling
- Photodynamic therapy
References
Bolognia, Jean L., ed. Dermatology, pp.1676-1693. New York: Mosby, 2003.
Freedberg, Irwin M., ed. Fitzpatrick's Dermatology in General Medicine. 6th ed, pp. 365, 719. New York: McGraw-Hill, 2003.
Actinic keratosis
See also in: External and Internal Eye,Hair and Scalp