From Big Medical Encyclopedia

HYPERKERATOSIS (grech, hyper-+ a keratosis [y]) — an excessive thickening of a corneous layer of epidermis.

Mikropreparata of cuts of skin of the person, the skin characterizing a ratio of layers are normal also at a hyperkeratosis (proliferatsionny): 1 — horn; 2 — granular; 3 — aculeiform; 4 — basal (at the left — normal skin).

Can result from excess formation of a keratin (see. Keratins ), when granular and aculeiform layers of epidermis are thickened (proliferatsionny G. — fig.), e.g. at red flat herpes (see. Deprive red flat ), or owing to a delay of peeling (retentsionny G.) when granular, and sometimes and the aculeiform layer, is thinner normal, napr, at some forms ichthyosis (see). At the heart of proliferatsionny G., according to Omuletsky (A. Omulecki, 1969), intensive synthesis of a keratin as a result of increase in functional activity of cells of epidermis lies, and at retentsionny, according to the Flash and Ezoda (R. of Flesch, E. Esoda, 1963) — increase in contents in a corneous layer of mucopolysaccharides.

See also Keratoza .

G. M. Tsvetkova.