Ultrasonographic characterization of the nails in patients with psoriasis and onychomycosis

ObjectiveThe study aimed at assessment of ultrasound (US) in diagnosing nail psoriasis and onychomycosis.MethodsOne hundred subjects were included: the psoriatic patients group (n = 25), the onychomycosis patients group (n = 25) and the control group (n = 50). Nail psoriasis severity index (NAPSI) score and onychomycosis severity index were used to assess the patients, in addition to performing nail culture. The thickness of right index and thumb nail plate (NP) and nail bed (NB) was measured by US. The following parameters were also assessed: contour and echogenicity of the NP, NB focal lesions, interpolate space, distal interphalangeal joint (DIJ) changes, proximal nail fold (PNF) changes and distance between proximal NP and DIJ.ResultsThumb NP thickness in psoriasis, onychomycosis and control groups was 0.80 ± 0.14 mm and 0.77 ± 0.21 mm, and 0.61 ± 0.09 mm respectively. The thumb NB thickness in psoriasis, onychomycosis and control groups was 2.05 ± 0.32 mm, 2.13 ± 0.32 mm, and 1.79 ± 0.23 mm respectively. Psoriatic nails show preserved interplate space and DIJ changes. Onychomycotic nails show loss of interplate space proximally, swollen PNF and decreased Plate/DIJ distance.ConclusionUS nail measurements and characters can differentiate between psoriasis and onychomycosis.