Dermatoscopy is a useful, non-invasive method in the diagnosis of various dermatological diseases. Dermatoscopy of non-pigmented skin lesions shows additional morphologic features, such as cutaneous vascular pattern, scale color and scale distribution pattern, and background color. Dermatoscopy can be useful tool in differential diagnosis in palmoplantar dermatoses. The most specific dermatoscopic features of hand eczema include yellowish-orange globules, yellowish scales and yellowish crusts. Light red background color, regular vascular distribution pattern, dotted vessels and white scale color have been reported in previous studies as dermatoscopic features of palmoplantar psoriasis. Dotted vessels can be seen in various dermatoses, such as psoriasis, eczema, lichen planus, porokeratosis and keratodermas. The distribution pattern and color of the scales are also important in the differential diagnosis of palmoplantar dermatoses. Previous studies have shown that scales are mainly localized in skin furrows in patients with tinea manum. Patchy distributed, homogeneous, structureless, orange areas were reported in palmar keratoderma due to pityriasis rubra pilaris. Amber scales, white-to-pinkish background; sparse whitish scales were reported in palmar keratoderma due to mycosis fungoides. Dermatoscopical findings of palmoplantar area can help in the differential diagnosis of various dermatoses.
Part of the book: Dermatoscopy
Psoriasis is a chronic inflammatory skin disease, which is mainly characterized with erythematous indurated plaques with squams such as many other inflammatory skin diseases. Also different clinical subtypes of psoriasis can show distinctive clinical appearances. As an example, inverse psoriasis does not have squams and resemble erythema intertrigo; or erythrodermic variant cannot be distinguished from other erythroderma causes sometimes. From reasons above, differential diagnosis of psoriasis should be done carefully to manage a chronic and long-term treatment required disease appropriately. Histopathologial examination is gold standard technique for certain diagnosis; however, dermoscope is a noninvasive and easily applicable diagnostic tool with high specificity. In this chapter, we discuss dermoscopic differential diagnosis of psoriasis.
Part of the book: Psoriasis