Dermatology Eczema / Psoriasis

Is it nail psoriasis or fungus?

Psoriasis on toenails and fingernails can look a lot like fungus. While fungal infections are contagious, psoriasis is not.

Psoriasis is an autoimmune disease that causes the immune system to become hyperactive. This change in the immune system triggers skin cells to grow much quicker than normal.

Nail fungus is a type of infection. People often pick up the infection at a nail salon or gym, but it is possible to get a fungal infection from a range of places.

Knowing the difference between nail psoriasis and nail fungus can prevent symptoms from getting worse, and support proper treatment.

Fast facts on nail psoriasis and fungus:

  • Psoriasis causes scaly, painful, peeling patches of skin that can itch or become infected.

  • Fungal infections of the toenails and nails do not affect other areas of the body.

  • It is impossible to distinguish nail psoriasis from nail fungus without medical testing.

  • Fingernail and toenail psoriasis look quite similar.

What is the difference between nail fungus and psoriasis?

Fungal infection in the fingernails.
Psoriasis of the nails and fungal infections appear similar, and can have similar symptoms. Knowing the difference is essential for treatment.


About half of people with psoriasis develop psoriasis symptoms on the nails – more frequently on the fingernails than the toenails.

Most people with psoriasis symptoms on the nails develop psoriasis elsewhere, too. In some people with psoriasis, nail symptoms are the first to appear.


A person can pick up a fungal infection by coming into contact with something a person with a fungal infection has touched.

Nail fungi thrive in moist, warm environments, so people whose hands or feet are often wet are especially vulnerable.

However, people with a weakened immune system due to diabetes or HIV may develop sores that do not heal after a fungal infection, so prompt treatment is important. The earlier the treatment is started, the better the results will be. Delayed treatment can permanently damage the nail bed.

Symptoms of psoriasis on toenails and fingernails

A few specific clues suggest that psoriasis, not fungus, is the problem. Some tell-tale signs of fingernail and toenail psoriasis include:

Recent trauma

Symptoms of nail psoriasis often appear after an injury to the affected area. Because the toes are often crammed into tight shoes or exposed to the ground, it is possible to overlook a small injury, such as a cut or bruised toe.

Psoriasis may also begin with a broken or damaged nail, painful hangnail, a finger slammed in a door, or an injury while getting a pedicure or manicure.

While an open wound on the hands or feet makes it easier for fungal infections to enter the body, the wound will not trigger a fungal infection. Most people with fungal infections do not experience an injury before the infection begins.

Other psoriasis symptoms

Nail psoriasis in toenails. <br>Image credit: JVO27, (2015, August 16.)</br>
Nail psoriasis may be characterised by scaly, dry patches of skin surrounding the nail, and changes in the nail shape and size.
Image credit: JVO27, (2015, August 16.)

People who have other symptoms of psoriasis who develop nail symptoms are likely to have psoriasis of the nails. Symptoms of psoriasis include:

  • red, scaly, or peeling patches of skin

  • itchy, dry patches of skin

  • skin patches that open, bleed, and do not heal

  • smooth, raw-looking patches of skin

  • tiny bumps on the chest or back of the body

  • silvery-white patches on the skin

Different types of psoriasis produce different symptoms, and the symptoms may change or get worse over time.

Nail pitting

Psoriasis displays a tell-tale pattern of yellowing nails that develop progressively deeper pits. The nails might start out looking a little dry, then develop ridges that ultimately form deep pits or even holes.

Nail loss

Psoriasis tends to cause the nails to detach from the nail beds, leading to nail loss. The nails may fall off completely or break off only in pieces. Before the nail falls off, a gap usually develops between the nail and the fingertip.

Fungal infections tend to change the shape and appearance of the nails but rarely cause the nails to fall off.

Nail color and structure changes

Keratin is a protein that helps form the skin and nails. Nail psoriasis sometimes causes too much keratin to grow under the nail. This is called subungual hyperkeratosis. People with this symptom may notice a white, chalky substance under the nail. When this happens to the toenails, the feet may hurt from the pressure of shoes pushing down on the nails.

Symptoms of fungus on toenails and fingernail

Fingernail with onychomycosis infection.
Although nail infections are most common in toenails, they may occur in fingernails as well.

Fungal infections usually affect the toes, not the fingernails. This is because the feet are more likely to come into contact with fungus from walking barefoot.

People who get regular manicures or whose hands are often wet, however, are equally vulnerable to fungal infections of the fingernails. Some characteristics of fungal infections of the nails include:

Color of the nail

Fungal infections can cause hyperpigmentation, which means that the color of the nail changes. The infection may begin as a faint gray, greenish, or brown spot that gets darker and wider over weeks or months. Psoriasis does not typically cause dark spots on the nail.

Nail shape changes

Unlike psoriasis, fungal infections do not cause pits in the nails. Instead, the nails tend to change shape over time. They may thin or develop thick patches, and sometimes break.

Nail growth pattern

Nail fungus often grows with the nail. It attaches to a specific portion of the nail, and as the nail grows and that portion of the nail moves, so too does the fungus. Because fungus tends to spread, though, this pattern can be hard to detect.


Both psoriasis and fungal infections tend to get worse with time. Psoriasis, however, does not spread with contact like fungal infections do, so fungal infections tend to spread more quickly. People with fungal infections of the toenails may notice color changes in between the toes, or other signs that the infection has spread to the skin between the toes.

The infection may also eventually spread to the nails or spread from one toe to multiple toes.

Outlook for psoriasis and fungus

Knowing the difference can prevent people with fungal infections from spreading the infection to other people. However, people with nail symptoms of either condition should not self-diagnose.

Psoriasis and fungus are not mutually exclusive. It is possible to have both at the same time. People with psoriasis may also be more vulnerable to fungal nail infections, complicating the process of getting an accurate diagnosis.

Only a doctor can confidently determine the cause of changes in the fingernails and toenails. And prompt medical care can address symptoms of both fungal infections and psoriasis.

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