Actinic keratosis, also known as solar keratosis, is a dry, scaly patch of skin that presents as a result of chronic exposure to sunlight. Most people with the condition do not report significant symptoms, although the condition can progress to a type of skin cancer, squamous cell carcinoma, in severe cases without treatment.
The patches on the skin may vary from a few millimeters to several centimeters in diameter and are usually pink, red or brown in color. The area surrounding the patch can often become thickened and, in some cases, the patch may protrude from the skin in a horn or spike shape.
Areas of the skin that are subject to frequent exposure to sunlight may be affected by actinic keratosis. Common sites include:
- Rims of ears
- Scalp (of bald men)
Most people with actinic keratosis do not experience significant symptoms and the patches eventually heal spontaneously. However, some patients may report soreness, itchiness or discomfort due to the patches on the skin.
In rare cases without appropriate treatment, actinic keratosis can progress to squamous cell carcinoma. When this occurs, the patch of skin typically grows more quickly, often creating a raised area of skin, which may be painful.
Actinic keratosis is primarily caused by exposure to ultraviolet (UV) radiation in sunlight. As a result, people who spend a lot of time in the sun (e.g., outdoor occupation) are more likely to be affected.
Additionally, some skin types are more sensitive to the UV radiation and, accordingly, these individuals are at a higher risk of the condition. Risk factors include:
- Fair skin
- Blond or red hair
- Green, blue or hazel eyes
Diagnoses of actinic keratosis is usually made with a simple inspection of the skin, including the physical appearance and feel of the area, with is usually rough.
In some cases, a biopsy may need to be taken to investigate the possibility of squamous cell carcinoma.
Not all cases of actinic keratosis require treatment and, for some patients, the best course of action is watchful waiting to see if the patches change with time. However, treatment is often required to remove the patches, particularly if there is a concern about the progression to squamous cell carcinoma.
Possible treatment options for actinic keratosis include:
- Topical creams (e.g. 5-fluorouracil cream or imiquimod cream)
- Topical gels (e.g. diclofenac gel or ingenol mebutate gel)
- Photodynamic therapy
- Laser resurfacing
The treatment decision depends primarily on the severity of the actinic keratosis and the need for its removal.
For patients with actinic keratosis, it is important to protect the skin from further exposure to UV radiation in sunlight and reduce the risk of additional patches developing. Sun protection recommendations that should be followed include:
- Stay in the shade between 10am and 2pm, when the UV radiation is strongest.
- Wear appropriate protective clothing (e.g. a long-sleeved shirt and wide-brimmed hat) when in sun.
- Apply 30+ sunscreen to exposed skin half an hour before going outside, even on cloudy days.
It is also important that self-checks of the skin are made by the patient regularly to assess any changes such as the presentation of new patches. Patients should be encouraged to seek medical advice if they notice any significant changes.