It’s not unusual to have problems with your nails. Most of the time, it’s a simple matter of filing away a rough edge or clipping a hangnail. But sometimes it’s more complicated than that.

If your fingernails or toenails are discolored, cracking, or separating from the nail bed, you may have a problem with nail psoriasis or nail fungus.

Psoriasis is an autoimmune disease. It can cause red, scaly patches on the skin. Nails and skin are closely related. If you have psoriasis of the skin, you may also develop psoriasis of the nails.

Nail fungus, or onychomycosis, is an infection caused by fungi.

Although these conditions may look similar, there are a variety of differences between them.

The symptoms of nail psoriasis and nail fungus are quite similar, and it may be difficult to tell them apart. It’s important to know which you have so you can treat it properly.

Here’s a comparison of the symptoms of each condition:

Symptoms of nail psoriasisSymptoms of nail fungus
Pitting, thickening, or deformation of the nailsPitting, thickening, or deformation of the nails
Yellowing or browning of the nailsDarkening of the nail color
Nails detach from the nail bed (onycholysis), creating gaps that can become infected by bacteriaProgressive distortion in nail shape
Chalky buildup under the nail that causes the nail to lift (subungual hyperkeratosis)Nails may be brittle and appear dull
Tenderness or pain if there is buildup under the nailsFoul odor

Nail fungus is fairly common. It usually starts with a white or yellow spot under the tip of your fingernail or toenail. At first, it may be easy to ignore.

Sometimes, the fungal infection can spread between your toes and onto the skin of your feet. That’s when you have a case of athlete’s foot, or tinea pedis.

Nail psoriasis almost always occurs in people who have general psoriasis. It tends to affect fingernails more often than toenails.

Anyone can develop a fungal infection of the nail, but more people get toenail fungus than fingernail fungus. A foul odor may indicate that you’re dealing with a fungus.

It’s possible to have both nail psoriasis and a fungal infection. According to the , about 35 percent of people with nail psoriasis may also have a fungal infection.

Up to 50 percent of people with psoriasis and at least 80 percent of people with psoriatic arthritis have problems with their nails, according to the .

It’s unclear why some people with psoriasis have a nail problem while others don’t.

Fungi are tiny organisms that flourish in warm, moist environments. Showers and swimming pools are among their favorite hiding places. Any separation between your nail and nail bed is an open invitation for fungi to migrate. Even a microscopic cut in your skin can let them in.

You’re more prone to nail fungus as you age. Men, especially those with a family history of fungal infections, develop nail fungus at a higher rate than women. You’re also at increased risk of nail fungus if you:

  • sweat a lot
  • work in a moist environment, or your hands or feet are often wet
  • walk barefoot around public swimming pools, gyms, and showers
  • wear socks and shoes with poor ventilation
  • have an immunosuppressive illness, such as HIV
  • live with someone who has nail fungus

People who have circulatory problems or diabetes are also at increased risk. Any injury to the nail bed can also make you more vulnerable to nail fungus.

Unless you’re certain which condition you’re dealing with, you won’t know how to treat it effectively.

If your symptoms are very mild, you may not need treatment.

When you have discoloration, pitting, or cracking of your nails, you should seek a medical opinion. That’s especially important if you have psoriasis or diabetes.

In the meantime, take these steps:

  • Keep your feet clean and make sure to dry them thoroughly.
  • Keep your nails short and neat.
  • Make sure any manicure and pedicure tools you use are clean and disinfected.
  • Change your socks twice a day.
  • Wear shoes that fit properly and allow your feet to breathe.
  • When visiting a public pool or locker room, wear shower shoes whenever possible.

Nail psoriasis can be hard to treat. You can try topical medications, but they don’t always work. Other treatments may include , corticosteroid injections to the nail bed, and light therapy (phototherapy). In severe cases, nails can be surgically removed so new nails can grow in.

Nail fungus can be treated with over-the-counter antifungal agents. If that doesn’t work, your doctor may want to do a culture to determine the cause. Prescription-strength topical or oral antifungals may be necessary. Parts of the diseased nail can be removed.

Be patient, as nails grow slowly. It may take a long time to see the results of treatment.

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