Actinic Keratosis: Causes, Symptoms & Treatment

Actinic keratosis or solar keratosis is a slowly progressive skin damage due to years of exposure to light (especially UV light). The definition, causes, diagnosis, progression, treatment, and prevention of actinic keratosis are explained below.

What is actinic keratosis?

Actinic keratosis or solar keratosis is a slowly progressive skin damage due to years of exposure to light (especially UV light). In this process, damage occurs to the keratinizing epidermis. The formation of an actinic keratosis after damage often takes several years. Actinic keratosis is considered a precancerous condition, which means that the development of skin cancer is possible after years. Actinic keratosis is one of the precancerous lesions with a tendency to malignant degeneration in 5-10% of cases. Therefore, actinic keratosis is also considered as carcinoma in situ, that is, an early stage of a tumor without invasive growth and formation of one or more malignant daughter tumors in other organs.


Actinic keratosis occurs primarily in people with skin types I and II. However, men are more often affected than women. The reason is often occupational prolonged exposure to sunlight in road and construction workers or agricultural workers or sailors. The incidence of actinic keratosis (number of new cases) is increasing in Germany because of hobbies such as water sports, tennis, hiking or skiing, as well as travel to countries with higher levels of UV radiation. The latency period of actinic keratosis until the onset of visible skin damage can last up to 20 years. In the meantime, the DNA of the skin cells is damaged (mutation). Gradually, the mutated skin now multiplies and displaces the normal skin.

Symptoms, complaints and signs

Actinic keratosis is manifested by superficial skin changes in areas of the body that are frequently exposed to sunlight – that is, primarily the face, forehead, head, and forearms. Small reddish spots develop on these areas of the body, which in the course of the disease develop into sharply defined reddish nodules that are about the size of a lentil and have grayish-brown keratinization. In the affected area, the skin feels rough. If the keratinization is pronounced, small skin horns may form, causing pressure pain. In most cases, the skin changes occur over a large area on the entire body or in small groups on certain parts of the body. In the later stages, actinic keratosis may also be manifested by hardening, bleeding and redness of the affected skin. In addition, the skin lesions increase in size and occasionally develop into ulcers. Pain or excessive keratinization of the skin as well as itching may also occur, especially if the actinic keratosis develops into skin cancer. If a spinalium has already formed, further symptoms may occur, such as sensory disturbances and signs of paralysis in the affected area. Eventually, extensive skin lesions occur, during which the skin scales and continues to harden.

Diagnosis and course

Actinic keratosis forms preferentially on the head and arms, regions of the body that are increasingly exposed to UV light. The so-called “sun terraces of the face” are the forehead, nose, ear, mouth and, in men, the bald head. However, forearms and the backs of the hands also often develop actinic keratosis. Before an actinic keratosis develops, sharply defined reddish discolorations of the skin (round, oval) appear individually or in several places. Usually, these discolorations have a rough surface. As described above, the mutated displaces the normal skin and a brown thickened keratosis develops, which may vary in thickness. One form of actinic keratosis is cornu cutaneum. In this case, a very severely altered skin forms that looks like a horn.Five to ten percent of patients with actinic keratosis develop a malignant tumor when the basement membrane of the skin is breached. This is often an invasive squamous cell carcinoma. If patients are also immunocompromised, the proportion of malignant degeneration of actinic keratosis is increased up to 30% of cases. The development of malignant degeneration often takes years. Actinic keratosis is usually suspected on the basis of its clinical appearance and characteristics.Likewise, the professional or private situation is addressed. However, the final diagnosis of actinic keratosis can only be made by histological examination after biopsy.


Actinic keratosis can be treated very effectively in the early stages. Treatment options-such as cryotherapy, laser, or excision of the focus-usually proceed without complications. During treatment, minor injuries may occur, which bleed a little and heal over the course of a few days. If actinic keratosis is not treated, it can develop into spinalioma. This subtype of white skin cancer is much more difficult and complicated to treat than actinic keratosis. The development of white skin cancer occurs in about ten percent of all cases of untreated actinic keratosis. The outbreak of spinalioma occurs about ten years after the appearance of the first spot on the skin, which can be traced back to an actinic keratosis. Spinaliomas tend to grow deep into the tissue and proliferate there. Spinaliomas not infrequently form metastases, initially in the surrounding lymph nodes, and later predominantly in the lungs. Actinic keratosis appears in the early stages in the form of white patches, mainly on the face and hands. If left untreated, the spots persist, which can have a negative effect on the psyche of particularly sensitive people. Withdrawal and social isolation are then not infrequently the result.

When should you go to the doctor?

In many cases, this disease is diagnosed relatively late, and irreversible consequential damage can occur. For this reason, a doctor should be consulted whenever skin complaints occur that are unusual and also do not disappear on their own. There is no spontaneous healing in this disease. As a rule, a visit to the doctor is necessary when there are extensive changes on the skin. Different areas of the body can be affected by these changes. It is not uncommon that the face is also affected by the skin complaints. Furthermore, these complaints can lead to inferiority complexes or depressive moods, in which case a psychologist can be consulted. Medical treatment is also necessary in case of papules or cornification of the skin. The earlier this treatment is initiated, the lower the risks of serious consequences. As a rule, a dermatologist can be contacted directly, who can treat the symptoms properly. In acute emergencies, the patient should visit the hospital.

Treatment and therapy

The therapy of actinic keratosis is carried out on the one hand by removing the foci by curettage (scraping or scraping), excision (cutting out) or cryotherapy (cold therapy). Electrosurgical or laser treatment is also possible. On the other hand, topical medications can also be used to treat actinic keratosis. For larger areal forms of actinic keratosis, photodynamic therapy can also be used. This uses light in combination with a photosensitizer (light-active substance) and oxygen present in the tissue. Primarily, the substance to be applied is not toxic to the body, but excitation with light in a certain wavelength as well as oxygen produces reactive toxic substances that damage the regions of actinic keratosis. Usually, photodynamic therapy is scarless.

Outlook and prognosis

In this disease, severe damage to the skin occurs. In this case, the damage usually occurs continuously through various exposures, so that in most cases the symptoms do not appear and become apparent until later in life. There are changes in the appearance of the skin in various places. Changes in the area of the face in particular are very unpleasant for patients. Partly, the affected persons then suffer from a reduced self-esteem. Furthermore, pain can occur in the affected regions, which can make everyday life more difficult. The skin is reddened and may be covered with papules. As a rule, the quality of life is reduced by this disease and the skin becomes relatively rough. Furthermore, various cancers can occur if the skin has been severely damaged. The disease can be treated by removing the affected areas of skin. This usually does not result in scarring.However, the affected person must protect his skin from direct sunlight afterwards.


The prophylaxis or prevention of actinic keratosis consists of consistent light protection. In doing so, the same should be done especially in childhood, since a latency period of 10 to 20 years is known. This is especially true for people with skin types I and II, as they are particularly at risk.


Local treatment of actinic keratosis with ointments or gels is usually accompanied by severe inflammatory changes in the treated skin area. Depending on the type and mode of action of the drug used, these last for some time after completion of treatment: As part of aftercare, it is important to keep the affected skin areas clean and to avoid skin irritation from clothing or excessive touching if possible. In general, a healing ointment containing the active ingredient panthenol may be applied after consultation with the physician to accelerate the reconstruction of the skin. Products containing cortisone should not be used, as they would cancel the desired inflammatory process necessary for the treatment of actinic keratosis. If the skin lesions are removed with the help of cryotherapy or surgically, small wounds are also left behind, which must be protected from contamination and kept dry until they heal. The most important aftercare measure is lifelong sun protection of all skin areas at risk using appropriate clothing and sunscreens with a high sun protection factor. To protect the particularly sensitive skin of the head and face, affected persons should always wear a sun hat or cap when in the sun. Regular self-examinations of the skin and biannual to annual checkups with a dermatologist ensure that newly appeared actinic keratoses can be treated at an early stage

What you can do yourself

Although actinic keratosis does not usually cause severe discomfort and is not acutely dangerous, it is nonetheless an early form of skin cancer, which is why those affected should definitely consult a specialist. Since the disease is triggered by UV radiation from the sun or in solariums, it can be prevented by taking preventive measures. A whole series of protective measures are easy to implement. In particular, people with type I fair skin, who are especially at risk, should never expose themselves to the summer sun for long periods without sunscreen. Sunscreens should have at least sun protection factor 30 and a UVA/UVB broadband filter. Extensive sunbathing, however, increases the risk despite protective products. Since the sun’s rays are particularly intense on the water and in high mountains, people who have already developed the first signs of actinic keratosis should avoid such situations or take additional precautions. Affected areas of the body must be covered in these cases not only with sunscreen, but also with clothing. If the treating physician recommends therapy with an immunomodulator, it is essential that the patient apply the active substance to the skin before sleeping for several weeks, as prescribed by the physician. Inconsistency in the application of an immunomodulator may jeopardize the success of the therapy.