keratosis

keratosis

 [ker″ah-to´sis]

any horny growth, such as a wart or callosity.

actinic keratosis a sharply outlined wartlike or keratotic growth, which may develop into a cutaneous horn, and may become malignant; it usually occurs in the middle aged or elderly and is due to excessive exposure to the sun. Called also senile or solar keratosis. (See Atlas 3, Part F).

keratosis follicula´ris a slowly progressive autosomal dominant disorder of keratinization characterized by pinkish to tan or skin-colored papules on the seborrheic areas of the body that coalesce to form plaques, which may become crusted and secondarily infected; over time, the lesions may become darker and may fuse to form papillomatous and warty malodorous growths. Called also Darier's disease and Darier-White disease.

keratosis palma´ris et planta´ris palmoplantar keratoderma.

keratosis pharyn´gea horny projections from the tonsils and pharyngeal walls. Called also pharyngokeratosis.

keratosis pila´ris hyperkeratosis limited to the hair follicles.

keratosis puncta´ta a hereditary hyperkeratosis in which the lesions are localized in multiple points on the palms and soles.

seborrheic keratosis (keratosis seborrhe´ica) a benign, noninvasive tumor of epidermal origin, marked by numerous yellow or brown, sharply marginated, oval, raised lesions.

senile keratosis (solar keratosis) actinic keratosis.

ker·a·to·sis

, pl.

ker·a·to·ses

(ker'ă-tō'sis, -sēz),

Any lesion on the epidermis marked by the presence of circumscribed overgrowths of the horny layer.

[kerato- + G. -osis, condition]

keratosis

(kĕr′ə-tō′sĭs)

n. pl. kerato·ses (-sēz)

Excessive growth of horny tissue of the skin.

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ker′a·tot′ic (-tŏt′ĭk) adj.

keratosis

Dermatology A condition characterized by ↑ keratin production See Actinic keratosis, Seborrheic keratosis, Stucco keratosis.

ker·a·to·sis

, pl. keratoses (ker'ă-tō'sis, -sēz)

Any lesion on the epidermis marked by the presence of circumscribed overgrowths of the horny layer.

[kerato- + G. -osis, condition]

keratosis

(ker?a-to'sis) (-to'sez?) plural.keratoses [ kerato- + -osis]

1. Growth of the horny layer of the skin; a callus, callosity, or keratoma.

2. Any condition of the skin characterized by the formation of horny growths or excessive development of the horny growth. keratotic (?a-tot'ik), adjective Synonym: keratoma

ACTINIC KERATOSIS: Actinic skin damage on forehead and scalp

actinic keratosis

Abbreviation: AK

A rough, sandpaper-textured, premalignant macule or papule caused by excess exposure to ultraviolet light. AKs often appear on facial skin (such as near the eyes, on the nose, on the ears, or the lips) and the parts of the body that receive the most sunlight exposure. Prevention of AKs depends on limiting one's exposure to sunlight, beginning in childhood and continuing throughout life. See: illustration

Treatment

Liquid nitrogen destroys these lesions and prevents them from progressing to other cancers of the skin.

Synonym: solar keratosis See: sunscreen

keratosis follicularis

Darier's disease.

keratosis nigricans

Acanthosis nigricans.

oral keratosis

Keratinization of the mucosa of the mouth to an unusual extent, or in locations normally not keratinized, as a result of an inherited autosomal dominant gene or the more common effect of tobacco and other carcinogens.

keratosis palmaris et plantaris

A congenital abnormality of the palms and soles, characterized by a dense thickening of the keratin layer in these regions.

keratosis pharyngis

Horny projections from the pharyngeal tonsils and adjacent lymphoid tissue.

keratosis pilaris

Chronic inflammatory disorder of area surrounding the hair follicles. It is often found in patients with atopic dermatitis. Synonym: lichen pilaris; lichen spinulosus

Symptoms

The disorder is characterized by an accumulation of horny material at follicular orifices of persons with rough, dry skin. It is most pronounced in winter on lateral aspects of thighs and upper arms with possible extension to legs, forearms, and scalp.

Treatment

There is no specific therapy, but keratolytic lotions may be of some value.

keratosis punctata

Discrete horny projections from the sweat pores of the palms and soles.

SEBORRHEIC KERATOSES ON BACK

seborrheic keratosis

A benign skin tumor that may be pigmented. It is composed of immature epithelial cells and is quite common in older adults. Its etiology is unknown.

Symptoms

Keratoid, nevoid, acanthoid, or verrucose types occur in older adults and in those with long-standing dry seborrhea, on the face, scalp, interscapular or sternal regions, and backs of the hands. The yellow, gray, or brown sharply circumscribed lesions are covered with a firmly adherent scale, greasy or velvety on the trunk or scalp but harsh, rough, and dry on the face or hands.

Treatment

Thorough curettage is effective. This leaves a flat surface that becomes covered with normal skin within about 1 week. Pedunculated lesions can be removed surgically. Cautery may produce scarring and should not be used.

Synonym: wart, seborrheic See: illustration

keratosis senilis

An inaccurate synonym for actinic keratosis, which is caused by accumulated ultraviolet light exposure, not by aging.

smokeless tobacco keratosis

Tobacco pouch keratosis.

snuff keratosis

Tobacco pouch keratosis.

solar keratosis

Actinic keratosis.

STUCCO KERATOSIS: White warty lesions of the dorsum of the fist

stucco keratosis

Benign papules, typically found on the lower extremities, histologically related to seborrheic keratoses. See: illustration

tobacco pouch keratosis

A white, corrugated lesion found on the oral mucosa usually in the muccobuccal fold where chewing tobacco has been habitually placed.

Synonym: smokeless tobacco keratosis; snuff keratosis

keratosis

Small white patches in the skin arising from excessive local reproduction of the horny outer cells, so that more than the normal amount of KERATIN is formed. Solar keratosis, caused in the elderly by over-exposure to the sun, is a precancerous condition. Keratosis may also affect the hair follicles causing baldness, the outer and middle ears causing obstruction of the ear canal and CHOLESTEATOMA, and the mucous membranes of the lip and of the throat.

Keratosis

A skin disease characterized by an overgrowth of skin, which usually appears discolored.

Mentioned in: Hyperpigmentation

ker·a·to·sis

, pl. keratoses (ker'ă-tō'sis, -sēz)

Any epidermal lesion marked by circumscribed overgrowths of horny layer.

[kerato- + G. -osis, condition]