Swelling and redness of the skin around the nail is called paronychia. This is an infection of the skin at the bottom of the nail (cuticle). If the infection is acute (has a rapid onset), it is usually caused by bacteria. It may respond to warm soaks but will often need to be drained by a doctor. A chronic paronychia occurs when a cuticle becomes inflamed or irritated over time. Sometimes, yeast will take advantage of the damaged skin and infect the area as well. Therapy begins with keeping the skin dry and out of water. If the problem continues, a physician should be consulted. Antibiotics are not often used but may be necessary in severe infection.
Dermatophytes — fungus that grows on the skin, hair and nails but don’t penetrate tissues of the body. Athlete’s foot or Trichophyton rubrum is the most common dermatophyte and can actually infect the toenails. Infection can also begin by touching objects that have dermatophytes on them, such as nail clippers, nail files, socks, shoes, shower floors, etc. Dermatophytes are the cause of most fungal toenail infections.
Use soap and water to wash your feet, and dry well, including between toes. Trim your toenails -- straight across -- to keep them shorter than the end of your toe. Make sure the tools you use are clean, too. Wash clippers and files with soap and water, then wipe with rubbing alcohol. You might be tempted to cover up discolored nails with polish, but don't. Your nail bed can't "breathe," which keeps fungus from going away.