Flat Non-pigmented Lesions on the Upper Limb

The clinical evaluation of isolated, hyperkeratotic lesions has a wide differential diagnosis ranging from actinic keratosis and squamous cell carcinoma to inflammatory lesions such as psoriasis and contact dermatitis. Dermatoscopy helps in narrowing the differential diagnosis. Porokeratosis is part of the differential diagnosis of multiple or isolated scaly lesions. Most cases of porokeratosis are easily diagnosed with dermatoscopy, but some cases display subtle findings and might be challenging or overlooked. The use of a standard surgical pen (“ink-test”) may highlight helpful dermatoscopic clues, reassuring or ruling out the diagnosis of porokeratosis [1].