Actinic keratosis is permanent damage to the epidermis. Typical signs are reddish-brown, rough and scaly patches on areas that have been exposed to more sun exposure. This includes the face, forehead, bald head, ears, décolleté and forearms as well as the backs of the hands. Even if the skin damage is benign and only progresses slowly, it is considered a precursor to a type of white skin cancer, squamous cell carcinoma.
Actinic keratosis mainly affects middle-aged and older people, especially those who have been exposed to intense sunlight and UV radiation for many years in their professional and private lives. Because the skin damage develops into skin cancer in about every tenth affected person, everyone should have actinic keratosis treated medically. Only occasionally do the keratoses regress spontaneously and with consistent sun protection.
 |
| Actinic Keratosis |
These skin changes may or may not be actinic keratosis. Because a light keratosis is not so easy to recognize for the layperson. The first signs are small reddish spots that appear when the skin thins after too much sun exposure and dilated blood vessels become more prominent (technical term: telangiectasia). It is typical of actinic keratosis that the spots usually no longer heal by themselves, but remain permanent.
In addition, the following are characteristic of actinic keratosis:
- Reddened, reddish, yellow-brown spots
- Solid scales
- Superficial cornifications and small skin horns
- Skin changes more palpable than visible (feeling like stroking sandpaper)
- Sharply defined nodules and papules
- Size from 0.5 to 1 centimeter
- Signs on sun-exposed areas such as the face (preferably the bridge of the nose, forehead, the edges of the ears and the lower lip), on the sparsely haired scalp and on the bald head, on the ears, on the décolleté, the forearms and the backs of the hands
Actinic keratosis often does not appear as a single spot or skin damage alone, but there are small groups of these skin changes, e.g. on the scalp or in a section, or they are distributed over a large area (technical term: multiple actinic keratosis).
Anyone who discovers a suspicious skin change or skin area that no longer heals should have it examined by a specialist.
Treatment
Each actinic keratosis should be treated by a dermatologist, as it is not certain from which of the skin changes skin cancer develops. There are many treatment options available to remove and destroy the patches of skin. Which one the dermatologist chooses in consultation with the person concerned depends on where exactly the skin changes are located, how many lesions there are and how large they have grown. For example, actinic keratoses on the face are treated differently than on the forearm, for example, since it is important that the appearance of those affected is not affected.
In the facial area, doctors often opt for treatments with gels and creams because they can achieve good cosmetic results, even if they require a longer treatment period than surgical or mechanical methods. In addition, large-area actinic keratoses can be effectively treated with creams and gels, where surgical procedures can sometimes be very stressful for those affected. Depending on the spread, different methods are also combined.
Medication
- Diclofenac: The painkiller and anti-rheumatic drug diclofenac (a non-steroidal anti-inflammatory drug, NSAID) has proven to be very effective and has few side effects as a three percent gel combined with hyaluronic acid in the treatment of actinic keratoses. The gel is applied and gently rubbed in morning and evening over a period of 90 days. According to several studies, eight out of ten people responded to the treatment. Side effects are rare and show up as slight itching, redness and dry skin. It is important that you avoid sunbathing during the treatment.
- 5-Fluorouracil: The active ingredient 5-Fluorouracil inhibits cell growth (technical term: cytostatic). Applied locally as an ointment or solution, after a strong inflammatory skin reaction, the altered cells die and heal. Treatment usually lasts between two weeks and two months. Side effects can be unpleasant skin reactions, which is why the drug is not tolerated by all those affected.
- Ingenol mebutate: Ingenol mebutate, an ingredient found in the milky sap of garden spurge (Euphorbia peplus), has recently been approved for the treatment of flat, sparsely keratinized actinic keratoses. The active ingredient only needs to be applied locally for two to three days. The inflammatory response that activates immune cells can also cause swelling, pain, and redness.
- Imiquimod: Imiquimod activates the immune system by causing an inflammatory response and eventual healing. Those affected apply the active ingredient as a cream to the skin for several weeks before going to sleep. About eight out of ten of the treatments should lead to a complete healing of the actinic keratosis. Redness and itching, pain and burning occur as side effects.
- Chemical peeling (chemosurgery): In the case of extensive actinic keratoses in the facial area, doctors often resort to caustic agents such as trichloroacetic acid or high-percentage fruit acids (alpha-hydroxy acids) – also known as chemical peeling. Pain, inflammatory reactions and, rarely, scarring are undesirable effects.
- Laser therapy: Laser therapy is particularly useful for individual skin changes. Almost all cases of actinic keratosis can be completely removed with the laser. Short-term side effects include pain, inflammation, changes in skin color and scarring.
- Photodynamic Therapy (PDT): PDT works in two steps. First, the actinic keratoses are pretreated for several hours with creams or gels that contain special active ingredients (5-aminolevulinic acid, methyl 5-amino-4-oxopentanoate). They increase the sensitivity of damaged skin cells to light. In the second step, the skin is irradiated with a light source and possible cancer cells are killed.
- Curettage (also curettage): The superficial surgical removal with a "sharp spoon" or a curette is called curettage. The advantages are that local anesthetic is often not required and the actinic keratosis is usually completely detached. Possible side effects include bleeding and scarring.
- Cutting out the skin areas (excision): An excision is the first choice in treatment if the doctor wants to rule out that a squamous cell carcinoma has already formed. In this way, he can have the removed tissue examined for histology.
- Freezing (cryotherapy): Liquid nitrogen with a temperature of up to -196 °C is used for cryotherapy, which is why side effects such as blistering, slight pain and then, during healing, scarring and changes in skin color can occur. The chances of success of cryotherapy are high, even if the actinic keratosis returns in the next few months in every tenth person affected.
- Removal by electric current: Smaller actinic keratoses can be destroyed with little effort using electric current impulses (electrodesiccation).
Causes, risk factors and frequency
Actinic keratoses are caused by strong UV radiation that repeatedly and persistently affects the skin. The damage to the skin can be as much a result of the UV radiation from excessive sunbathing as it can be caused by the artificial UV rays from solariums. Normally, the top layer of skin can defend itself quite well: it repairs damage itself and repairs changes. However, if the exposure to UV radiation is too high, it can no longer keep up with the repair. Diseased skin cells not only remain, they multiply until actinic keratosis develops.
Risk factors
Risk factors include being light-skinned, frequent sunburns in childhood, being bald and being male. People who spend a lot of time outdoors in their leisure time or at work have a higher risk of actinic keratosis, as do passionate solarium users.
Risk factors in detail:
- Male gender
- Increased age
- Leisure activities with a lot of UV radiation
- Light skin type with reddish or blond hair and light eyes
- Outdoor profession, e.g. farmers, mountain guides, construction workers
- Immunosuppression, e.g. after an organ transplant or due to an HIV infection
- Hereditary diseases such as reduced skin pigmentation (e.g. albinism) or defect in the skin repair system (e.g. moonlight disease)
- Geographical location (Australia, proximity to the equator)
- Possibly also an infection with the human papilloma virus
Frequency
In the past, actinic keratosis mainly occurred in people over 50 years of age. Therefore, the typical skin changes are also referred to as senile keratosis or senile cornification. Due to changed leisure habits such as increased outdoor activities, sunbathing and more visits to the solarium, younger people around the age of 30 are increasingly affected.
Prevention
Actinic keratosis can be prevented very well by dealing sensibly with solar radiation and artificial UV light (see also sunburn). This includes:
- Avoiding the midday sun (between 11 a.m. and 3 p.m.)
- Refrain from going to the solarium
- When the sun is shining, seek shade, wear sun protection clothing and a sun hat
- Apply a suitable amount of sunscreen with a high sun protection factor and UV-A or UV-B protection
- Pay attention to sun protection, especially for children
- For outdoor jobs, advocate sun protection (awnings, reduction of working hours in the midday sun).
- Regular self-check of the skin