An ingrown toenail (onychocryptosis) occurs when part of the nail penetrates the skin, which can often result in an infection the ingrown nail can also apply pressure in the nail fold area without penetrating the skin - this is not strictly an ingrown toe nail, but can also be painful (a corn/callus is also common down the side of the nail and is a reaction to this pressure, rather than the nail in fact penetrating the skin).
 
What does an ingrown toe nail (onychocryptosis) look like:

Usually the side of the nail penetrates deep and it is hard to see the edge of the nail. The severity of appearance of the nail will vary. Some will just have a nail that appears deeply embedded down the side or sides of the nail. In some the corner or a little spike of nail may penetrate the skin, just like a knife. This can result in an infection and the growth of proud flesh (granulation tissue). The toe will then be red, inflamed and painful.

What are the symptoms of in ingrown toenail (onychocryptosis):

Pain is the main indication of an ingrown toe nail - usually just starting as some minor discomfort. This may be just the pressure from the side of the nail or it may be because the nail has actually penetrated the skin down the side of the nail. The toe is not necessarily impure, but this can develop after the nail penetrate the skin to become ingrown. The infection can spread, making the toe red and inflamed (paronychia) a collection of pus may also develop.
 
What causes an ingrown nail (onychocryptosis):

Poor cutting of the nail is most usually blamed as being the cause of an ingrown toe nail, but this is not necessarily the case the following factors are concerned in the cause of ingrown toenails (onychocryptosis):

    * the primary risk factor is the shape of the nail - a nail that is more bent from side to side rather than being flat is more likely to become an ingrown nail (incurvated nails). Some nails go down the side into the nail fold area for a relatively large distance. A big piece of the nail is almost vertical rather than being horizontal. The most harsh of these types of nail is called a 'pincer nail' in which both side of the nail are very curved the shape of the nail is more often than not inherited (congenital), but it can be influenced by trauma and/or shoe pressure.
    * Poor cutting of these types of nails can leave a pointed corner (or if worse, a small spike) that will initially cause symptoms by putting pressure on the skin and then later go through the skin. Trimming too far down the sides is a ordinary cause of an ingrown toe nail.
    * footwear that is tighter is more likely to add to pressure between the skin in the nail fold and nail, increasing the risk on an ingrown nail.
    * previous trauma to the nail may change the shape of the nail, making it more flat to becoming an ingrown nail
    * pressure from the toe next to the nail that has ingrown can sometime be a factor
    * A 'chubby' or fleshy toe is more likely to have a nail grow into it. Those whose feet swell are a lot are more prone to having this occur.

Self treatment of the ingrown nail (onychocryptosis):

The cornerstone of self treatment and avoidance of ingrown toe nails involves cutting the nail straight across to allow the corners to protrude, so that they do not penetrate the skin. Cut the toe nails straight across without tapering the corners. However, this can be hard if the nail is very curved down the side. In this case DO NOT 'dig' down the sides - seek professional help for this (see below).

It is a myth that a V should be cut in the end of the nail to luxury an ingrown toe nail. The apparent reasoning behind this is that if you cut a V in the nail, the edge of the nail will grow together as the nail grows out. This does not happen - the shape of the nail is strong-minded by the growing area at the base of the toe, not the end.

Avoid wearing shoes and socks that are too tight. Keep feet clean to prevent the ingrown nail from becoming infected. Those with poor circulation or diabetes should not do any self management of ingrown toenails but see a Podiatrist see below to find a Podiatrist.

See below for how a Podiatrist would run an ingrown toenail (onychocryptosis).