Actinic keratoses are common, persistent, scaly lesions found on the sun-exposed areas of the skin in elderly individuals with fair skin. They represent intraepithelial dysplasias of the skin and are the most frequent precancerous lesions in humans. Their size can range from a few millimeters to large confluent plaques measuring several centimeters, especially in patients with significant photoaging.
Actinic keratoses are caused by the long-term harmful effects of ultraviolet radiation on the keratinocytes of the epidermis. They are the most common precancerous lesions of human skin and are now considered intraepithelial neoplasms (in situ squamous cell carcinoma) of the skin. They occur more frequently in men, which is usually related to the shorter hair length on the male scalp.
High-risk groups for developing actinic keratoses include individuals with prolonged sun exposure due to occupational reasons (farmers, fishermen, etc.) or recreational activities (outdoor athletes, mountaineers, etc.), transplant recipients, and patients under chronic immunosuppression. The risk of developing squamous cell carcinoma in patients with actinic keratosis is estimated at 10 to 20%, especially in cases with multiple lesions and duration longer than 10 years.
Actinic keratoses clinically present as erythematous macules or plaques that sometimes coalesce, with adherent yellowish-white scales on their surface. When palpated, they have a sandpaper-like texture. Attempting to remove the scales causes pain and leaves slight bleeding, which is a characteristic clinical diagnostic sign.
The clinical spectrum includes, besides typical actinic keratosis, the expanding pigmented actinic keratosis, hypertrophic actinic keratosis, lichenoid actinic keratosis, Bowen’s type actinic keratosis, and actinic cheilitis. Actinic keratoses are also considered precursor lesions to the formation of cutaneous horns.
A. In non-pigmented actinic keratoses, the following are observed:
- “Strawberry pattern” on a red background
- Non-focused vessels around open hair follicles
- White rosettes (whitish dots resembling a “rosette” or four-dot sign)
B. In pigmented actinic keratoses, the following are observed:
- Gray-brown granules and globules around follicular openings
- Mixed ring-like and granular pattern
- Rhomboid structures
There are several therapeutic options for managing actinic keratoses. Depending on the specifics of each case, the dermatologist’s experience, and the equipment available, each dermatologist can choose among the following:
- CO₂ – Er:YAG laser
- Cryotherapy
- Electrocoagulation
- Topical application of 5‑FU
- Topical application of imiquimod cream
- Topical application of diclofenac cream
- Topical application of ingenol mebutate
- Topical photodynamic therapy
- Surgical excision – histological examination if invasion to squamous cell carcinoma is suspected
To prevent the appearance of actinic keratoses, the individual must practice photoprotection. It is recommended to avoid solar radiation, especially between 10 a.m. and 4 p.m., seek shade, and avoid sunburns. Complementary sun‑protection measures include choosing appropriate clothing (e.g., hat, sunglasses) and using an umbrella at the beach. Let us not forget that the use of sunscreens with a high protection factor against UVB and UVA radiation should be a daily practice during sunny months on sun‑exposed areas of the body. Regular dermatological examinations, dermoscopy, and mapping by a dermatologist, particularly in high‑risk individuals, constitute an important measure for timely prevention and treatment.
Finally, self‑examination for any changes in the clinical features of one’s body helps in the early detection of recurrences or new lesions.
Actinic keratoses are precancerous lesions, because over time they are likely to evolve into a type of cancer, squamous cell carcinoma. However, only a dermatologist can diagnose the lesion and recommend the appropriate method of management.
Skin with extensive photoaging and actinic keratoses requires, in addition to regular dermatological examinations, periodic self‐examination. Any change in a preexisting lesion, particularly in sun‐exposed areas (such as the onset of pain, bleeding, or morphological changes in shape, size, color, etc.), as well as the appearance of new lesions, should prompt the patient to seek immediate dermatological assessment.
Absolutely YES! Mapping and dermoscopy constitute our most important weapon for the prevention and timely diagnosis–treatment, NOT ONLY of melanocytic (melanoma) but also of non‑melanocytic cancerous and precancerous skin lesions, such as actinic keratoses.
Additionally, the presence of actinic keratoses and the chronic, cumulative exposure to ultraviolet radiation that preceded their appearance constitute a predisposing factor for the potential development of other malignant skin tumors.