History and exam

Key diagnostic factors

common

single or multiple scaly macules or plaques

Most commonly, lesions are pink, skin-colored, or yellowish, ill-defined, irregularly shaped, small (1 to 5 mm), rough, scaly macules or plaques, on sun-exposed areas of skin. [Figure caption and citation for the preceding image starts]: Regular actinic keratosisFrom the collection of the Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine [Citation ends].com.bmj.content.model.Caption@7d49929c

scaly lesions with a hyperkeratotic surface

May present as a hyperkeratotic lesion. [Figure caption and citation for the preceding image starts]: Hyperkeratotic actinic keratosisFrom the collection of the Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine [Citation ends].com.bmj.content.model.Caption@2d109650

well-defined, scaly, brown lesions

Pigmented AKs resemble solar lentigo.[1]

lesions resembling seborrheic keratosis, melanocytic nevus, and early malignant melanoma

Spreading pigmented AKs may occur.[5]

hypertrophic conical-shaped protuberances growing from the surface of the skin

Typical of a cutaneous horn.

scaly red roughness with induration, fissuring, and ulceration of the lower lip and the vermilion border

Typical of moderate to severe actinic cheilitis.[1][4][Figure caption and citation for the preceding image starts]: Actinic cheilitisFrom the collection of the Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine [Citation ends].com.bmj.content.model.Caption@293e3ac5

lesion on sun-exposed area of body

The forehead, bald areas of the scalp, ears, lower lip, and dorsum of the hands and forearms are the most common anatomic areas involved.[38]

uncommon

skin-colored, papillomatous, elevated wartlike papules

Typical of verrucous AKs.

plaques with very mild scale over very thin shiny skin

Typical of atrophic AKs.

violaceous well-defined papules with fine white lines on the surface

Typical of lichen planus-like or lichenoid AKs.

Other diagnostic factors

common

evidence of sun damage to skin

Solar elastosis, cutaneous furrowing, and wrinkles are more likely to be present in sun-exposed areas.[4]

uncommon

pruritus or bleeding

Mild pruritus may be present.

Bleeding may occur if lesions are scratched.

Risk factors

strong

chronic exposure to UVB radiation

Causes damage to keratinocyte DNA, and induces mutations on the tumor suppressor gene p53, leading to the perpetuation and clonal expansion of keratinocytes with damaged DNA.[31][36][37]

More than 80% of AKs are located on the head and neck, and on the dorsum of forearms and hands (chronic UV-exposed areas).[38]

There is an inverse risk of developing AKs with latitude; risk decreases with increasing distance from the equator (latitude 0°).[39][40]

light-colored skin, freckling, and albinism

Melanin absorbs UVB rays to help protect human skin from developing AKs.[28][30] People with light-colored skin (Fitzpatrick skin types I and II) are 6 times more likely to develop AKs than darker skin types.[22] Freckling in childhood leads to increased risk for developing AKs.[16][17][41]

After acute sun exposure, patients who burn without tanning are twice as likely to develop AKs as those who tan without burning.[22]

The incidence of AKs in people with albinism >20 years old is 91%.[15][16][17][42]

age >40 years

Ninety percent of patients >80 years old have been reported to have at least 1 AK, compared with 10% of patients in the third decade of life.[4][14]

male sex

Men are much more commonly affected than women.[19][20][21]

immunocompromise

Patients with organ transplants are at 250-fold higher risk of developing aggressive AKs.[42][43]

xeroderma pigmentosum

Associated with an increased risk of AKs early in life.[4][16][17]

Use of this content is subject to our disclaimer