Common causes include localized infection, minor injury to the matrix bed, or severe systemic illness. It is sometimes a side effect of chemotherapy or x-ray treatments for cancer. A new nail plate will form once the cause of the disease is removed. Onychomycosis, also known as tinea unguium, is a contagious infection of the nail caused by the same fungal organisms which cause ringworm of the skin (Trichophyton rubrum or T. mentagrophytes, rarely other trichophyton species or Epidermophyton floccosum ). It can result in discoloration, thickening, chalkiness, or crumbling of the nails and is often treated by powerful oral medications which, rarely, can cause severe side effects including liver failure. Mild onychomycosis sometimes responds to a combination of topical antifungal medication, sometimes applied as special medicinal nail lacquer, and periodic filing of the nail surface. For advanced onychomycosis, especially if more than one nail is infected, systemic medication (pills) is preferred. Home remedies are often used, although their effectiveness is disputed. Onychophosis is a growth of horny epithelium in the nail. Onychoptosis is the periodic shedding of one or more nails, in whole or part. This condition may follow certain diseases such as syphilis, or can result from fever, trauma, systemic upsets or adverse reaction to drugs. Onychorrhexis also known as brittle nails, is brittleness with breakage of fingernails or toenails. Paronychia is a bacterial or fungal infection where the nail and skin meet. Koilonychia is when the nail curves upwards (becomes spoon-shaped) due to an iron deficiency.
It was found that in all operations involving this complication the preoperative sterilization was done with chlorhexidine. The ototoxicity of chlorhexidine was further confirmed by studies with animal models.Several other skin preparations have been shown to be potentially ototoxic in the animal model. These preparations include acetic acid, propylene glycol, quaternary ammonium compounds, and any alcohol-based preparations. However, it is difficult to extrapolate these results to human ototoxicity because the human round window membrane is much thicker than in any animal model. Other medicinal ototoxic drugs
At high doses, quinine, aspirin and other salicylates may also cause high-pitch tinnitus and hearing loss in both ears, typically reversible upon discontinuation of the drug. Erectile dysfunction medications may have the potential to cause hearing loss. However the link between erectile dysfunction medications and hearing loss remains uncertain.Previous noise exposure has not been found to potentiate ototoxic hearing loss. The American Academy of Audiology includes in their position statement that exposure to noise at the same time as aminoglycosides may exacerbate ototoxicity. The American Academy of Audiology recommends people being treated with ototoxic chemotherapeutics avoid excessive noise levels during treatment and for several months following cessation of treatment. Opiates in combination with excessive noise levels may also have an additive effect on ototoxic hearing loss. Ototoxicants in the environment and workplace
Ototoxic effects are also seen with quinine, pesticides, solvents, asphyxiants, and heavy metals such as mercury and lead. When combining multiple ototoxicants, the risk of hearing loss becomes greater.