General diseases-associated nail disorders may be classified into 5 types according to their clinical impact. Type I refers to nail disorders considered as peculiar features among the various symptoms of general disease such as peri-ungueal vascular dilatation, onycholysis, Beau lines, opaque nails or melanonychia. Type II refers to nail disorders with a strong clinical value such as Terry's nails, Muerhrcke's lines or koilonychia. Type III refers to nails disorders presenting as significant syndromes of several diseases such as yellow-nail syndrome of subungueal splinter haemorrhages, and type IV to specific disorders considered as true keys for diagnosis such as digital hippocratism, Bazex's acrokeratosis, Koenen's tumor, or nail hypoplasia. In type V are included drug-induced nails disorders especially after chemiotherapy or antiretroviral therapy.