Patient undergoing a skin examination and treatment advice on classic dermatology. A specialist in skin health and skin diseases examines and explains the skin of the female patient in the bright rooms of the Frankfurt dermatology practice.

Actinic keratoses (cornification disorders)

Actinic keratoses

Actinic keratoses are the result of genetic changes in skin cells caused by sun exposure. They are considered the early stages of white skin cancer (squamous cell carcinoma). They mostly occur in sun-exposed areas of the body, ie on the head (formerly hairy scalp), on the décolleté, on the face (often on the nose or forehead), on the backs of the hands or arms.


They manifest themselves as spots with a rough surface and are therefore more palpable than visible. Redness is usually added to the sandpaper-like change.


The anamnestic asks whether the person concerned was often exposed to the sun without protection in the past. The clinical picture together with the palpation of the roughness provides sufficient information about the present situation. A dermatoscopic or reflected-light microscopic imaging with a final histological cell examination after a sample collection confirms the suspected diagnosis.


Drug therapy with certain active ingredients, such as fluorouracil as a cell poison, can be applied selectively to the actinic keratoses in the form of creams or ointments. These become inflamed easily and new skin formation is stimulated. This can be done in a mild form over several weeks or in a severe form with more severe reactions over three days. In addition, selective cryotherapy with -180 °C cold nitrogen is considered an alternative. If there is field cancerization, i.e. a large-scale infestation, photodynamic therapy is recommended.

Photodynamic Therapy

With a fractioned Laserthe skin is opened slightly with a laser and a cream containing the active ingredient methylaminolevunilate is applied. This is followed by a two-hour stay outdoors. This does not have to mean that the treated areas have to be exposed to the sun. A minimum lux number already ensures a reaction of the active ingredient on the skin. After the two hours, the skin is treated in the practice.

In the following three days, severe reactions in the form of redness and scab formation develop, which can last up to two weeks. The more pronounced the cancerization, the stronger this is expressed in the subsequent skin reaction. Despite the unusual sight, this is a desired side effect, since the regeneration of the skin causes the actinic keratoses to disappear. After three days, there is also a medical check-up. Normally, all newly occurring skin changes recede and leave behind freshly formed, smooth, healthy skin.

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