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1. hypertrophy of the horny layer of the skin, or any disease characterized by it.
2. hypertrophy of the cornea. adj., adj hyperkeratot´ic.
epidermolytic hyperkeratosis a hereditary autosomal dominant form of ichthyosis, present at birth. Characteristics include generalized redness of the skin and severe hyperkeratosis with small, hard wartlike scales over the entire body, accentuated in areas that flex or bend and sometimes involving the palms and soles. In infancy and childhood, there are recurrent bullae, most often on the lower limbs.
follicular hyperkeratosis a skin condition characterized by excessive development of keratin in hair follicles, resulting in rough, cone-shaped, elevated papules, the openings of which are often closed with a white plug of encrusted sebum. Deficiencies of vitamins A and E, B complex vitamins, and essential fatty acids have all been implicated in the etiology. Called also phrynoderma.
hyperkeratosis lenticula´ris per´stans an autosomal dominant skin disorder, usually occurring in the third or fourth decade of life, characterized by pink, red, or yellow to brown scaly papules on the lower leg and back of the foot, and sometimes on the trunk, thigh, arm, back and palm of the hand, or sole of the foot.
characterized by localized lesions, keratosis palmaris and plantaris, and elevated IgE, associated with hyperkeratosis, hypergranulosis, and reticular degeneration in the upper epidermis; autosomal dominant inheritance, caused by mutation in the epidermolytic palmoplantar keratoderma gene (EPPK) on chromosome 17q. Generalized epidermolytic hyperkeratosis is present in bullous congenital ichthyosiform erythroderma.
Synonym(s): porcupine skin
Etymology: Gk, epi + derma, skin + lysis, loosening; Gk, hyper, excess + keras, horn + osis, condition
a rare autosomal-dominant form of ichthyosis with a high frequency of spontaneous mutations. Present at birth, it is characterized by generalized erythroderma and severe hyperkeratosis with small wartlike scales over the entire body, especially in body folds, and sometimes on the palms and soles. There are also recurrent bullae on the lower limbs. If sepsis and electrolyte imbalances are not treated correctly in neonates, morbidity can occur. Also called bullous congenital ichthyosiform erythroderma. See also ichthyosis.
epidermolytic hyperkeratosisOne of a range of genetic skin-blistering diseases caused by mutations in the genes for the protein keratin expressed mainly in the basal cells of the epidermis. Children are affected most severely. There is redness, blistering and scaling of the skin at the sites of pressure or trauma especially the elbows and knees. The blistering is worsened by heat but the blisters heal without scarring and become less frequent as the child gets older. The scaling, however, persists.
1. hypertrophy of the horny layer (stratum corneum) of the skin, or any disease characterized by it; the hyperkeratoses may have distinctive formats, e.g. annular (ring formations), basket-weave, compact, laminated.
2. hypertrophy of the cornea.
chlorinated naphthalene poisoning.
increased thickness of the keratinized epidermis of footpads in dogs and rarely cats. May be in response to trauma or associated with distemper (hardpad disease), or pemphigus foliaceus.
a form of ichthyosis in humans which is inherited as an autosomal dominant trait; there is severe degeneration of the granular layer of the epidermis.
a crusting dermatosis over bony prominences, face and chin of young dogs. See zinc-responsive dermatosis.
an abnormal thickening, sometimes with fissures, of the planum nasale of dogs. May occur in association with digital hyperkeratosis (see above) as a feature of distemper (hardpad disease). Also seen in pemphigus foliaceus and discoid lupus erythematosus.
see nasal hyperkeratosis, digital hyperkeratosis (above).
hyperkeratosis with non-nucleated cells present.
hyperkeratosis with nucleated cells present; called also parakeratosis.