Dermoscopy of facial nonpigmented actinic keratosis

The accuracy of clinical diagnosis of nonpigmented, facial actinic keratosis (AK) is often suboptimal, even for experienced clinicians.

To investigate the dermoscopic features of nonpigmented AK located on the head/neck that may assist the clinical diagnosis.

Forty-one nonpigmented AKs on facial sites were examined by dermoscopy for any consistent underlying features. Lesions were gathered from skin cancer centres in Australia, Austria, Italy and the U.S.A. All cases were diagnosed histopathologically.

Four essential dermoscopic features were observed in facial AK: (i) erythema, revealing a marked pink-to-red 'pseudonetwork' surrounding the hair follicles (95%); (ii) white-to-yellow surface scale (85%); (iii) fine, linear-wavy vessels surrounding the hair follicles (81%); and (vi) hair follicle openings filled with yellowish keratotic plugs (66%) and/or surrounded by a white halo (100%). These features combined, in 95% of cases, to produce a peculiar 'strawberry' appearance.

A dermoscopic model of 'strawberry' pattern is presented, which may prove helpful in the in vivo diagnosis of nonpigmented, facial AK. A limitation of this study is the lack of testing of the specificity of the described dermoscopic criteria in differentiating nonpigmented AKs from other nonpigmented skin lesions at this site.