Actinic keratosis, or solar keratosis, is a skin condition that occurs mainly on the areas of the body most exposed to sunlight, such as the face, neck, hands and scalp. This disorder is closely linked to chronic exposure to ultraviolet (UV) rays, and can affect anyone. But thanks to the knowledge we have today, preventing this condition is possible.
Causes and risk factors
The main cause of actinic keratosis is prolonged and unprotected exposure to sunlight or frequent use of tanning lamps. UV radiation damages the DNA of skin cells, promoting the appearance of precancerous skin lesions, i.e. initial lesions that can develop into skin cancer. Those who spend a lot of time outdoors for work or sports activities, especially without adequate sun protection, are at greater risk. In addition, factors such as a weakened immune system or advancing age further increase the likelihood of developing keratosis.
Let’s take a detailed look at the risk factors for actinic keratosis.
- Chronic unprotected exposure to sunlight or tanning lamps. People may fall into this category if they
work in the sun;
are bald or have thinning hair;
have suffered sunburn due to exposure to the sun. - Fair skin. Although actinic keratosis can affect anyone, it is definitely more common among people with fair complexions. People with phototype I and II have less natural protection of their skin against the sun, while those with phototype III-VI, who therefore have darker skin, are more protected.
- Posizione geografica. Più si è vicini all’equatore, maggiori sono le probabilità di sviluppare il disturbo perché:
I raggi solari colpiscono la superficie terrestre quasi perpendicolarmente. Di conseguenza, l’intensità della radiazione solare è più forte
All’equatore si hanno circa 12 ore di luce solare al giorno durante tutto l’anno, il che aumenta il tempo di potenziale esposizione al sole
Nelle regioni equatoriali i raggi solari attraversano una porzione più sottile dell’atmosfera, riducendo la dispersione dei raggi UV e aumentando la loro intensità al suolo - Geographical location. The closer you are to the equator, the greater the likelihood of developing the disorder because:
The sun’s rays strike the earth’s surface almost perpendicularly. Consequently, the intensity of solar radiation is stronger
At the equator, there are about 12 hours of sunlight per day throughout the year, which increases the time of potential exposure to the sun
In equatorial regions, the sun’s rays pass through a thinner portion of the atmosphere, reducing the scattering of UV rays and increasing their intensity on the ground - Weakened immune system, as in the case of:
- Therapies such as chemotherapy, radiotherapy and immunosuppressive drugs (often administered to organ transplant patients)
- Chronic diseases such as AIDS, uncontrolled diabetes and other autoimmune diseases
- Ageing: the natural ageing process can reduce the effectiveness of the immune system
- Omega 3 deficiency. A diet deficient in foods containing this precious fat, which is contained in certain fish (salmon, trout, mackerel, anchovies) but also in nuts, flaxseed and soya, can predispose to the development of actinic keratosis.
- Vitamin C and vitamin E deficiency. These vitamins possess antioxidant properties, i.e. they help counteract free radicals and damage caused by UV radiation. We find them in, for example, nuts, green leafy vegetables, such as rocket, broccoli or spinach, but also in fruit, especially red-orange-purple fruit, such as citrus fruits and berries.
- Stress. A high state of stress, particularly over a long period of time, can contribute to weakening the immune system, reducing the body’s ability to fight the damage caused by UV exposure.
- Age over 40. Actinic keratosis is more common after the age of 40 because damage to the skin caused by UV exposure gradually accumulates over time. Repeated and prolonged exposure to UV radiation causes damage to the DNA of skin cells, which may not become apparent until several decades later.
Symptoms
Actinic keratoses generally appear as rough, scaly patches, varying in colour from red to brown. They can range in size from a few millimetres to one centimetre in diameter and are irregular in shape, with contours that tend to be ill-defined. These lesions are often found by touch rather than sight, with the skin being dry and sensitive. This occurs mainly in the early stages of the disease, when the lesions are so small that they are difficult to detect with the naked eye. In some cases, keratoses may cause itching or tingling or even pain when touched.
They occur most frequently in the areas most exposed to the sun, such as:
- face, in particular the nose, but also the lips and ears or the skin around the eyes
- neck
- back of the hands
- arms and forearms
- legs
- scalp in bald people or people with little hair
When actinic keratosis is localised to the lips, one speaks of cheilitis, involving, in most cases, the lower lip.
Prevention
To prevent actinic keratosis, it is essential to take care of one’s skin and protect it from the sun’s rays from a young age. In particular, it is important:
- Apply sun creams with UV filters before exposure to the sun
- After sun exposure, apply specific products to maintain skin elasticity and combat oxidative stress
- In case of prolonged exposure to the sun, wear protective clothing
- Avoid exposure to direct sunlight during the hottest hours of the day, between 11 a.m. and 4 p.m.
- Do not use tanning beds
- Perform regular skin self-examinations to detect any changes or the appearance of new lesions at an early stage
To reduce the risk of developing actinic keratosis, it may also be useful to supplement certain substances that can counteract the harmful effects of sun exposure, such as:
- Vitamin C and E: as already seen, these powerful antioxidants help neutralise free radicals generated by sun exposure
- Green tea polyphenols: have anti-inflammatory and antioxidant properties that can protect the skin from UV damage and improve its elasticity
- Zinc, which contributes to normal DNA synthesis
- Copper, which plays a key role in the synthesis of collagen and elastin, proteins essential for maintaining healthy skin
- Uridine, important for RNA synthesis, promotes cell growth and repair
- Polypodium leucotomos, a tropical fern whose extract is known to have antioxidant, anti-inflammatory and photoprotective properties. It also improves the skin’s resistance to sun damage, increasing its natural defences against UV damage and reducing the formation of erythema and other acute reactions
Available treatments
Actinic keratosis, although initially a benign condition, is potentially capable of evolving into more severe forms: in 10-20% of cases it evolves into squamous cell or squamous cell carcinoma. For this reason, it is essential to consult a doctor to obtain an accurate diagnosis and to define the most appropriate treatment.
Actinic keratosis can be treated with different techniques, depending on the severity and number of lesions. Among the remedies that the dermatologist can prescribe after a thorough examination are:
- Application of topical creams to control actinic damage. Creams are available on the market to be applied immediately after sun exposure that keep the skin soft and supple, helping to combat oxidative stress and limit DNA damage due to exposure. In the case of manifestations of actinic keratosis, specific creams can instead be applied to help prevent the appearance of UV damage.
- Cryotherapy. Cryotherapy is one of the most common treatments for actinic keratosis, and works by applying liquid nitrogen at very low temperatures to the patient’s skin lesion. The rapid freezing causes ice crystals to form inside the actinic keratosis cells, destroying the abnormal cells.
- Laser surgery. The laser is used to remove the top layer of damaged skin in a precise and controlled manner. The laser’s high-energy light vaporises the top layer of the skin, removing the abnormal cells without significantly damaging the surrounding tissue. After the damaged cells are removed, the skin regenerates with new healthy cells.
- Photodynamic therapy. This technique involves applying a photosensitising cream agent to the lesion and then irradiating the lesion with a light source to selectively destroy abnormal cells.
La cheratosi attinica rappresenta un segnale di allarme per la salute della pelle, che necessita di un’attenta sorveglianza, per evitare che si trasformi in una patologia seria. Per questo motivo, la prevenzione e il monitoraggio costante delle lesioni cutanee sono di fondamentale importanza.
Sources:
https://www.skincancer.org/international/cheratosi-attinica/