Yellow Nail Syndrome The yellow nail syndrome is uncommon and its pathogenesis is still unknown. Linear nail growth is arrested or greatly reduced. The nails are thickened and transversely and longitudinally overcurved with disappearance of the cuticle. The nail color varies from pale yellow to dark…
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Green nail syndrome The yellow–green to green–black nail plate discoloration is due to the production of the pigments pyocyanin and pyoverdin by Pseudomonas aeruginosa. This discoloration is most often present in the subungual space created by onycholysis and less often in the lateral nail plate….
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Longitudinal melanonychia results from melanin production by nail matrix melanocytes and is most commonly due to simple activation of these melanocytes. It can also result from melanocyte hyperplasia as is found in a lentigo, nevus or melanoma. Clinically, melanonychia presents as one or more longitudinal…
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Splinter Haemorrhages appear as one or more red–brown to purple–black, thin longitudinal lines in the distal portion of the nail. The shape of the subungual hemorrhages is due to the longitudinal orientation of nail bed capillaries. The most common cause of splinter hemorrhages is trauma, followed…
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Apparent Leukonychia. The nails appear white because of abnormalities in the color of the nail bed and this is usually due to nail bed edema. Apparent leukonychia does not move distally with nail growth and the white discoloration fades with pressure. Nail bed pallor may be a non‐specific sign of…
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Onycholysis The distal nail plate is detached from the nail bed and usually appears white because of the presence of air in the subungual space. If an exogenous pigment is present, the nail may appear yellow (fungi and exudate) to green–black (pyocyanin). In addition to environmental trauma, the…
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Koilonychia (spoon nails) The nail plate is thinned and flattened with upward eversion of its lateral and distal edges, leading to a concave spoon-like shape. Koilonychia is common in infancy as a benign feature of the great toenail, although insome infants its persistence may be associated with…
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The nail plate loses its transparency and looks white because of the presence of parakeratotic cells within its ventral aspect. True leukonychia is white opaque discoloration caused by diseases that disturb distal nail matrix keratinization and it presents with three morphologic variants: Punctate…
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Trachyonychia (sandpapered nails) presents as a rough surface affecting all of the nail plate and up to 20 nails (20 nails dystrophy). The affected nails are opaque, lusterless and rough; the nail plate surface has longitudinal ridging due to fine superficial striations distributed in a regular, parallel…
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Onychorrhexis is characterised by longitudinal ridge and fissure of the nail plate. It is often associated with nail thinning, indicating damage to the nail matrix. It may caused by lichen planus, trauma, and tumors. It is also common phenomenon of age-related ridging of the nail plate. 脆甲症是指甲板的纵向脊和裂缝。它通常与指甲变薄有关，表明指甲基质受损。它可能由扁平苔藓，创伤和肿瘤引起。如果没有以上病变，就是年老体弱，甲板薄了。…
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