[Cosmetic nail products]

Cosmetic embellishment of fingernails involves the use of substance that harden either after the evaporation of solvents (varnishes) or after polymerisation (artificial acrylic nails, gel tips, glue-on artificial nails). Pathological reactions to cosmetics usually occur at a remote site for varnishes, and, most commonly, in situ with polymerising substances. Unvarnished artificial nails do not affect pulse oximetry readings, and in theory, patients are not required to remove them. However, a real problem of contamination via artificial nails exists. Increased carriage of pathological Gram-negative organisms and of Staphylococcus aureus and yeasts has been noted among nursing staff wearing artificial nails, both before and after fingernail cleaning. Fingernail fragility manifests itself through a number of different physical signs such as soft, breaking nails, with longitudinal or transverse fissures, showing distal doubling or friability. In some subjects, excessive manicuring with metal instruments or manicure sticks results in rolled onycholysis, of evocative appearance, or transverse onycholysis.