Hyperkeratosis

As hyperkeratosis (from Greek: hyper - over, keratos - Horn ) is defined as the excessive keratinization of the skin. The outermost layer of the epidermis, the stratum corneum, is a large area or only selectively thicker.

• 2.1 Mechanical stimuli
• 2.2 Arsenic as an environmental poison
• 2.3 UV - radiation
• 2.4 comedogenic substances
• 2.5 Genetic predisposition and metabolic changes

Subtypes

The underlying mechanism differs according to subtypes.

Proliferation hyperkeratosis

With the proliferation hyperkeratosis it comes to thickening of the stratum corneum, because the cell division in the basal layer accelerates expires. During the same period ie more keratinocytes are formed as a result creates more corneocytes.

Retention hyperkeratosis

In the retention hyperkeratosis (from Latin retentio = retention ), there is thickening of the stratum corneum to, because the shedding of corneocytes from the stratum is disjunctum disabled.

Causes

Hyperkeratosis may have exogenous and endogenous causes.

Mechanical stimuli

When mechanical stress (particularly by pressure) the skin to the increased formation of keratinocytes or corneocytes is stimulated as a result, the stratum corneum - limited to the claimed region - thick (proliferation hyperkeratosis).

The stratum corneum thickens in humans, especially at the soles of the feet as a result of the special burden of pressure (body weight) and friction. It formed calluses. Such changes are possible with the appropriate stress at other locations of the body.

Arsenic as an environmental poison

Hyperkeratosis may also indicate a chronic arsenic poisoning.

UV - radiation

Ultraviolet radiation can lead to hyperkeratosis and even to the formation of light calluses.

Upon impingement of UV radiation on the skin, the cell division in the basal stratum is accelerated. More keratinocytes migrate to the surface of the skin, the stratum corneum is thick (proliferation hyperkeratosis).

The therapeutic effect of UV light and sunlight in acne is therefore ambivalent: on the one hand, UV radiation has an antibacterial effect, on the other hand, it promotes the proliferation hyperkeratosis - even in the sebaceous follicle. This can lead to the formation of new comedones.

Comedogenic substances

Comedogenic substances promote the formation of comedones. This corresponds to a limited to the sebaceous follicle hyperkeratosis. In general, avoid comedogenic substances on the basis of their material properties, the exfoliation of corneocytes ( horny cells ) disjunctum from the stratum, so that it comes to retention hyperkeratosis.

Genetic predisposition and metabolic changes

Hyperkeratosis may be genetically predisposed or due to metabolic changes. Examples are the keratosis pilaris and hyperkeratosis with endogenous acne, chronic eczema and psoriasis.

In dogs occasionally occurs on a hereditary hyperkeratosis of the bales.

Treatment

For cosmetic and medical treatment for hyperkeratosis ( keratolysis ) more keratolytic agents are available. Androgen hyperkeratosis female patients may be treated hormonally. Pumice, Hornhautraspeln, Callus and mechanical peels are used for abrasive treatment of hyperkeratotic skin lesions.