People of different age groups could be affected by thick toenails but most often it a disease of the elderly. Thick toenails can be caused by numerous factors. Usually, the toenail thickness is 0.8 millimeters and when the thickness of the toenail is double, the term thickened toenails can be used for the condition. In medicine, the condition is also known as onychogryphosis.

A multitude of factors have been proposed which may cause thick toenails. Most common and often occurring are inadequate nutrition, an overall unhealthy condition of a person, trauma to the nail, and mainly fungal infections. Wearing of ill-fitting shoes whether or not they are too tight or too loose, might also become a cause, as they continuously injury the nails. There is a connection between thick toenails and skin diseases like psoriasis.

In athletes, especially soccer players, nail damage often goes unidentified and this could cause temporary thickening of the nail. The nail may be affected by continuous trauma, which may worsen the nail’s condition. Underlying onychomycosis, a standard infection, penetrates the roots of the nail bed and thickens the toenail.

Unlike a few other conditions of the toenail, which commonly occur in women, thickened toenails is more common in men due to the  pattern of their footwear and physical activity. It does not mean that women are exempted; they can also have this condition from time to time. But, the main brunt of onychogryphosis falls on the elderly, more than sixty years of age due to decreased immunity and circulation. Other diseases like diabetes and acquired immunodeficiency syndrome may also lead to thickening of the toenails.

Yellow discoloration of the toenails is a common warning sign of onychogryphosis, accompanied with thickening of the nails. Other warning signs of thickened toenails may be linked to the signs of the conditions causing them. For instance, in psoriasis multiple skin lesions will be present in addition to the thickened toenail or an infection of the nails. There could be a purulent discharge under the infected toenail. The toenail also may become a black toenail, depending on the root cause.

It is always better to prevent the disease than to choose a cure. By following a few simple measures, it is possible to either completely prevent or delay the process of toenail thickening. Maintaining proper hygiene of the feet, trimming nails frequently and wearing comfortable shoes, will help prevent this disorder. Certain home cures can help improve the condition, like soaking your feet in warm water and then thinning the nails with a file. Antifungal drugs are for thin nails and will not be an effective treatment for thick toenails.