History and exam

Key diagnostic factors

common

lesions appear "stuck-on"

This is the hallmark feature. Lesions can display a variety of colors and shapes, but usually they have their "pasted-on" or "stuck-on" appearance in common.

localization on torso or face

Most frequently found on the back and chest and then on the temple, scalp, and neck. However, they can occur on any part of the body, except on mucous membranes.

yellow or light- to dark-brown-colored lesions

Lesions can display a variety of colors.

slightly raised, flat surface lesions

Is a key diagnostic factor.

wart-like texture

Is a key diagnostic factor.

multiple lesions

May occur as a single lesion, but usually multiple lesions with the same clinical characteristics are found on the same patient.

painless

Lesions are painless, although they can itch and be irritated by clothing and friction.

itching (prurigo)

Lesions can cause intense itching.

Other diagnostic factors

common

round yellow-white horn pearls in the surface of lesions

Is a diagnostic factor.

Risk factors

strong

age over 50 years

From 65% to 100% of people over the age of 50 years are affected.[9]​[10]​​[22]​​ In a survey of workers in Germany, the prevalence of seborrheic keratosis was 1.4% in people ages between 16-20 years, 24.2% ages between 41-50 years, and 66.7% ages between 61-70 years.[9]

Fitzpatrick skin type I or II

White skin (Fitzpatrick skin type I or II) increases the risk of seborrheic keratoses compared with brown or black skin (Fitzpatrick skin type IV, V or VI).

family history

A family history of seborrheic keratosis is especially common in people with a large number of lesions. An autosomal-dominant inheritance pattern is suspected but not conclusively demonstrated.[1][7][14]

sun/UV exposure

Seborrheic keratosis often appears on areas of the body that have been exposed to UV radiation over a long period.

weak

Fitzpatrick skin type IV, V, or VI (dermatosis papulosa nigra)

A variant of seborrheic keratosis (dermatosis papulosa nigra) sometimes develops in people with brown and black skin (Fitzpatrick skin type V and VI). Multiple small (1 to 2 mm in diameter), dark brown or black soft papules usually start to appear in adolescence and are found on the face, neck, and chest.[23]

female sex (dermatosis papulosa nigra)

A variant of seborrheic keratosis (dermatosis papulosa nigra) is more common in women than men. Multiple small (1 to 2 mm in diameter), dark brown or black soft papules usually start to appear in adolescence and are found on the face, neck, and chest.

pregnancy

Development of seborrheic keratoses may be triggered by pregnancy.

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