Understanding Thickened Nails

There are several causes of very thick or crumbling nails. They can be caused by injuries or pressure from shoes. Fungal infections are a common cause. Diabetes, psoriasis, or vascular disease are other possible causes.

Closeup of big toe with thick nail.


Along with thickening, the nail may appear ridged, brittle, or yellowish. It may also feel painful when pressure is put on it. After a while, a thickened nail may loosen and fall off.


Because thickened nails may be a symptom of a medical condition, your doctor will look at your medical history. A test may be done to check for fungal infection. The thickness and color of the nail are examined carefully. This helps determine the cause.


  • For infection: Oral or topical antifungal medications may be used to treat infection. These can help prevent sores under the nail. They also keep the fungus from spreading to other nails.

  • For thick nails not caused by infection: Thinning the nail may be an option. This can be done by trimming, filing, or grinding.

  • For pain: If the nail causes pain, part or all of the nail can be removed with surgery. Never try to remove a nail by yourself.


Many nail problems can be prevented by wearing the right shoes and trimming your nails properly. Keep your feet clean and dry to help avoid infection. If you have diabetes, talk with your podiatrist or primary care doctor before doing any foot self-care.

  • The right shoes: Get your feet measured. Your size may change as you age. This is due to ligaments that loosen with age and allow the bones in your foot to change position or spread. Wear shoes that are supportive and roomy enough for your toes to wiggle. Look for shoes made of natural materials, such as leather, which allow your feet to breathe.

  • Proper trimming: To avoid problems, trim your toenails straight across. Then, file the edges with a nail file. If you can’t trim your own nails, ask your health care provider to do so for you.