Actinic keratoses

Actinic keratoses are precancerous skin lesions caused by the accumulated damage of ultraviolet (UV) radiation over the years.

They present as small rough, dry or scaly areas that appear mainly on the most sun-exposed areas.

Although many people consider them simply «spots» or «crusts», actinic keratoses are important because a small proportion can evolve into a squamous cell carcinoma, a type of skin cancer. For this reason, they must be assessed and treated by a doctor.

The areas where they appear most frequently are: the face, the scalp (especially in people with baldness), the ears, the nose, the décolletage, the back of the hands and the forearms.

The main cause is sun damage accumulated over years. Each sun exposure produces small lesions in the DNA of the skin cells. Over time, these lesions accumulate and some cells begin to grow abnormally.

Why do they appear from a certain age? Because the damage produced by the sun is cumulative. They do not appear because of getting older, but because of the sum of many years of sun exposure.

Why do some people have many and others none? Several factors are involved: the skin type (fair-skinned people have a higher risk), accumulated sun exposure, repeated sunburns (especially in childhood), outdoor professions or activities, personal history of skin cancer and a weakened immune system.

Why do new lesions keep appearing? Because sun damage affects all exposed skin, even areas where there are not yet visible lesions. This is why we speak of the concept of «field of cancerisation», that is, skin damaged by the sun with a risk of developing new actinic keratoses.

Many people notice the lesion with their fingers before seeing it in the mirror. Actinic keratoses usually present as:

• Plaques or spots rough to the touch.
• A rough or scaly surface.
• Pink, reddish, brown or skin-coloured colour.
• Crusts that appear and disappear.
• Persistent lesions.

In some cases they can cause itching, a burning sensation, mild pain when touched or occasional bleeding.

Their size usually varies between a few millimetres and one or two centimetres.

In most cases, diagnosis is made through clinical examination. The doctor will use a dermatoscope, which allows the characteristic structures of these lesions to be observed.

On some occasions, especially if there is a suspicion that the lesion has evolved into a squamous cell carcinoma, a biopsy may be necessary.

The rest of the skin will also be examined to detect other lesions related to sun damage.

One of the most frequent questions is: «Is it necessary to treat all actinic keratoses?» In most cases, yes. Although not all will evolve into cancer, we cannot currently predict which ones will.

Treatment will depend on the number of lesions, their location and the characteristics of each patient.

Cryotherapy

It consists of applying liquid nitrogen to destroy the lesion. It is one of the most used treatments when there are few actinic keratoses.

Topical treatments

When there are multiple lesions or a field of cancerisation, specific creams or gels prescribed by the doctor can be used. Among them are: 5-fluorouracil, imiquimod, diclofenac and tirbanibulin. These treatments eliminate both the visible lesions and other microscopic alterations.

Photodynamic therapy

It is a very effective technique for treating multiple actinic keratoses, especially on the face and scalp. It makes it possible to treat entire areas of damaged skin with excellent aesthetic results.

Other treatments

In some cases laser, curettage or surgical excision may be used if there is a suspicion of malignant transformation.

Why do they reappear? Because treatment removes the existing lesions, but does not erase the accumulated sun damage. This is why periodic check-ups and photoprotection are essential.

In addition to medical treatment, it is recommended to:

• Use sunscreen SPF 50+ every day.
• Wear a hat when there is sun exposure.
• Avoid the sun during the central hours of the day.
• Do not pull off the crusts.
• Examine the skin periodically.
• Attend the check-ups indicated by your doctor.

These measures reduce the risk of developing new lesions.

Seek medical assessment if a lesion:

• Grows rapidly.
• Bleeds easily.
• Ulcerates.
• Causes persistent pain.
• Has a lump or hardening.
• Does not heal.
• Clearly changes in appearance.

These changes may indicate evolution into a squamous cell carcinoma and require early evaluation.

• Myth: Actinic keratoses are just age spots. Fact: No. They are precancerous lesions related to accumulated sun damage.
• Myth: If they do not hurt, they do not need treatment. Fact: Many produce no symptoms and yet must be treated.
• Myth: They only appear in very old people. Fact: They can appear earlier in people with intense sun exposure.
• Myth: Removing them prevents them from coming back. Fact: Treatment removes the existing lesions, but new ones can appear if the skin continues to be exposed to the sun.
• Myth: Sunscreen is no longer useful once the lesions have appeared. Fact: Photoprotection remains essential to prevent new actinic keratoses and reduce additional sun damage.

• Actinic keratoses are precancerous lesions caused by accumulated sun damage.
• Not all evolve into cancer, but they must be assessed and treated.
• They usually appear on the most sun-exposed areas.
• Cryotherapy, topical treatments and photodynamic therapy are very effective options.
• Daily sun protection and medical check-ups are essential.
• Any lesion that grows, bleeds or changes in appearance should be evaluated as soon as possible.