Actinic Keratosis
Also known as: Solar keratosis, Sun spots (precancerous)
An actinic keratosis is a rough, scaly patch of skin that develops after years of sun exposure. It is most common on areas that have received the most ultraviolet light over a lifetime: the face, ears, scalp of people with thinning hair, backs of the hands, forearms, and lower legs. Actinic keratoses are regarded as precancerous, because a small proportion can progress to squamous cell carcinoma, a form of skin cancer, and because having them signals that the surrounding skin has had enough sun damage to be at risk. They are very common in fair-skinned people over 40 who have spent a lot of time outdoors. Treatment is straightforward and effective, and diligent sun protection prevents new ones from forming.
At a Glance
- Common symptoms
- A rough, dry, or scaly patch of skin, often easier to feel than to see, Patches that are flat or slightly raised and usually less than 2 cm across, Pink, red, brown, or skin-coloured patches, sometimes with a hard, wart-like surface
- Main treatments
- Cryotherapy: freezing individual lesions with liquid nitrogen, the most common treatment, Prescription creams or gels applied over several weeks to treat an area with multiple lesions, such as 5-fluorouracil, imiquimod, diclofenac, or tirbanibulin, Photodynamic therapy: a light-sensitising cream followed by exposure to a special light, useful for large areas
- Category
- Dermatological · Very common in fair-skinned adults over 40, especially in sunny climates
- See a doctor if
- Any new rough, scaly, or persistent patch on sun-exposed skin that lasts more than a few weeks
Symptoms
Causes
- Cumulative damage to skin cells from ultraviolet (UV) light from the sun
- UV exposure from tanning beds and sunlamps
- Damage to DNA in skin cells that leads to abnormal growth of the top layer of the skin
- A weakened immune system, which reduces the body's ability to repair and clear sun-damaged cells
Risk Factors
- Fair skin, blond or red hair, and blue or green eyes
- Age over 40, with risk increasing each decade
- A history of frequent sunburn or long-term outdoor work or hobbies
- Living in a sunny climate or at high altitude
- A weakened immune system, including from organ transplant medication
- Previous actinic keratoses or skin cancer
Diagnosis
- Examination of the skin by a doctor, often with a dermatoscope (a magnifying light)
- Skin biopsy if a lesion is thick, bleeding, growing quickly, or has not responded to treatment, to rule out skin cancer
- A full skin check for other sun-damaged areas and for skin cancers
Treatment
- Cryotherapy: freezing individual lesions with liquid nitrogen, the most common treatment
- Prescription creams or gels applied over several weeks to treat an area with multiple lesions, such as 5-fluorouracil, imiquimod, diclofenac, or tirbanibulin
- Photodynamic therapy: a light-sensitising cream followed by exposure to a special light, useful for large areas
- Curettage (scraping) or surgical removal of thick or suspicious lesions, with the tissue sent for examination
- Chemical peels or laser resurfacing for widespread damage in selected cases
- Regular follow-up skin checks, since new lesions commonly develop
- Supportive: daily broad-spectrum sunscreen, which has been shown to reduce new actinic keratoses and help existing ones regress
Prevention
- Apply broad-spectrum sunscreen (SPF 30 or higher) daily to exposed skin, and reapply every two hours outdoors
- Wear a wide-brimmed hat, sunglasses, and long sleeves in strong sun
- Seek shade between late morning and mid-afternoon when UV is strongest
- Never use tanning beds
- Check your skin regularly and have new or changing patches reviewed
- Ask your doctor about nicotinamide (vitamin B3) supplements, which have reduced new lesions in some studies of high-risk people
When to See a Doctor
- Any new rough, scaly, or persistent patch on sun-exposed skin that lasts more than a few weeks
- A lesion that becomes thicker, tender, bleeds, ulcerates, or grows rapidly, which may indicate skin cancer
- An actinic keratosis that returns after treatment
- You have many lesions, a weakened immune system, or a history of skin cancer and need a regular skin check
Frequently Asked Questions
Related Conditions
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