The fingernails and toenails may be affected by several conditions. Their main function is for protection, and their location predisposes them to injury. Small puncture wounds about the nails often provide an entry portal for germs so that infectious processes about the nails ensue secondarily. Primary infection of the nails proper by germs and fungi may also occur. Deficiencies of certain vitamins can result in certain abnormalities of the nails. Deformities in the normal growth pattern and secondary infections may be caused by habitual biting of the fingernails.
Onychosis is a general term applied to diseases and abnormalities of the nails themselves.
Paronychia or “runaround” is an infectious process in the overlapping edge of skin at the sides and base of the nails. It may be limited to one small area, or may extend about the entire nail. This results most commonly from infection of a “hangnail” and is seen frequently after manicuring. The inflammatory reaction forms a tense, throbbing, tender area which often results in small abscess formation. If a paronychia is allowed to go untreated, the infection may extend up the finger without limitation, to cause more serious involvement of other important structures. Surgical treatment rests with incision for drainage of any abscess pockets and excision of any dead tissue. Drugs to combat the infection must be administered, and sometimes splinting or heat applications are necessary.
Felon is the infection of pulp of the fingertip, usually the result of a small puncture wound which allows the admittance of germs. The fat pad at the fingertip becomes swollen and reddened, with throbbing pain. Like other infections, untreated felons may extend to involve other tissues without limitation. Encapsulated pus pockets usually develop. Treatment rests with adequate drainage of these abscesses and drugs to inhibit the bacteria from multiplying.
Ingrown nail (unguis incarnatus) is a common and disabling involvement of the nail edge. It is seen most generally on the great toe, usually the outer margin. It may be the result of injury or ill-fitting shoes, but most often it is caused by an ill-advised habit of trimming the corners of the nails down below the skin edge. The uncovered area at the tip of the side of the nail is subject to ulceration and invasion by germs. The resulting inflammation initiates the formation of new flesh (granulation tissue) over the denuded area. As the nail grows, the corner is forced into the mass of inflamed new tissue, further aggravating the area and producing even greater discomfort. The individual then usually trims the corner of the nail back still farther; further inflammation and swelling occur, and a vicious cycle of such events ensues until a very tender infected process is present at the side of the nail—actually an associated paronychia.
The prophylaxis of ingrown toenails rests with properly fitting shoes and proper cutting of the nails. They should be cut straight across so that the nail itself projects beyond the skin all along its free edge. The corners should not be rounded off, but rather left square to overlap the skin. Nor should the nails be cut too short.
Initial treatment of ingrown nails must be directed toward reducing the infection and inflammation to a minimum. This entails the use of drugs, hot soaks, drainage of any abscesses, protective splints, correct footwear, or combinations of any of these. When the inflammatory processes have been brought under control, anatomical correction may be undertaken. If the mass of new flesh in the path of the growing nail is small, it can often be cauterized with cautery agents or electrocautery, to allow the nail edge to grow out over it. In some early cases it can be compressed by a small wad of cotton between the nail edge and soft tissue, to allow the nail to grow over rather than into the tissue. Repacking daily or even oftener is necessary, until the nail edge is free. In further advanced cases, the nail must be made permanently more narrow. This can be accomplished only by making the nail root, as well as the nail, narrower. If the inflammation of the paronychium cannot be almost completely eliminated, wedge rcsection of the nail and the eponychium must be done. When the eponychium has only minimal infection, it may merely be reflected. In both the nail root is made narrower. Either type operation may allow primary closure of the resulting crater by sutures, or may necessitate packing type dressings to allow it to heal from below upward. Regional nerve block is usually the anesthetic of choice.