Thick toenails are often assumed to be caused by the growth of fungus under the toenails and in the toenail itself. In many cases, this assumption is correct, however there are other things that will make a toenail look thick and distorted - injury to the root of the nail can do it temporarily, while severe or repeated injury can permanently distort a nail. People who engage in sports such as soccer can experience this kind of damage.

Skin conditions such as psoriasis and eczema will distort a nail as well if the area around the nails is affected. This is because nails are really made up of dead skin cells that have been stacked together very tightly. Just as the skin becomes inflamed and irritated by a skin condition, the tissues around the root of the nail where the nail is produced become inflamed and this can be the cause of thick toenails.

If the problem is being caused by a fungus, other signs are usually present. Before thick toenails developed, there was probably some yellowish or brownish discoloration of otherwise healthy looking nail. The nail may have begun to separate from the nail bed and the discolorations and separation may have moved gradually from the nail tip toward the root. A fungus, growing in the nail bed and gradually sending out hyphae into the substance of the nail causes these typical signs and is often the cause of thick toenails.

Regardless of what is causing the problem, thick toenails can be reduced somewhat by careful filing and trimming. A nail file or emery board used against the upper surface of the nail will wear way some of the nail material. This is a good approach for both cosmetic and health reasons: the nail will look better, feel more comfortable in a shoe, and, if fungus turns out to be the cause of thick toenails, it will be easier to treat if the nail is thinner.

Topical treatments for fungal toenail infections are often not very effective because they don't soak into thick toenails very well. The challenge is to get the nail as thin as possible and then apply a preparation that has superior ability to penetrate down through the layers and contact the fungus. Over the counter pharmaceutical preparations are well known to be relative ineffective when fungus is the cause of thick toenails, however, some commercially available natural essential oils and other topical products have been found to have better penetration qualities. These include Tea tree oil and other essential oils such as oregano oil. These and other natural remedies may be the home cures of the future for fungal nail infections.