Incorrect nail cutting, where a spike may be left in the sulci (nail groove). This spike will be a source of irritation to the toe and if it breaks the skin can become infected which will repeatedly happen unless the spike is removed. The spike will hold the skin open which is a portal for bacteria to enter and cause infection,which is why when patients get antibiotics from their doctor and have finished the course of pills,the infection re-occurs a short time later.
Where the nail curves in, it may be difficult to adequately clear or round the edge or reach the spike. In nails such as these cutting straight across may not necessarily work, and help may be needed in clipping and clearing the side of the nail.Onychophosis – A normal nail where the skin has folded over the edge of the nail. This folding may happen in over-weight people, or those who wear tight shoes, or those that pronate or the feet roll inwards too much. The folded skin can thicken leading to a painful callus on the edge of the toenail. This can be removed with skilled scalpel work, in attemting to prevent reoccurance. The ingrown toenail that occurs as a result of a curving of the nail side due to repeated minor trauma.
Certain foot types such as Pes Plano Valgus ( flat feet) and structural problems with feet are a common cause of ingrown nails where the pronation of the feet make the inside of the toe roll into the shoe. Over time, this will mis-shape the nail and make it curve ( involution) or simpley the pressure will force the nail into the sulci. Sportsmen like footballers, runners or rugby players may sustain injury the side of the nail in the shoe or boot. Mens and womens fashion footwear are often the causative factor in creating this condition.