Slide show: How to trim thickened toenails

Your toenails can thicken for many reasons. These include an injury; skin conditions, such as psoriasis; tight or poorly fitting shoes; and fungal infections — as shown in this picture.

Among these, a fungal nail infection — onychomycosis (on-i-ko-mi-KO-sis) — is the most common cause of thickened toenails.

Soften your toenails by soaking them for 10 minutes in warm water. Dry your feet and toenails with a towel. Gently stroke the surface of the thickened toenails with an emery board to thin the nails. Now you're ready to trim them.

Nail trimmers similar to the trimmer shown here work best. They're lightweight, easy to grip and control, and can be purchased at most drugstores. Nail trimmers can be very sharp, however. Take extra caution when using them to trim your nails, especially if you have a disease that causes poor circulation or reduced sensations in your feet, such as diabetes mellitus or peripheral vascular disease.

Starting at the corner of your toenail, take small cuts to prevent splintering. Don't round your toenail at the corner. Instead, cut straight across. This will reduce your chances of developing an ingrown toenail.

Take small straight clips all the way across your toenail.

This thickened toenail has been trimmed correctly. The toes next to it need a similar straight cut. If you have a thickened toenail that's causing you embarrassment or worrisome pain, see your doctor.