Are Your Crusty Nails Psoriasis or a Fungus? How to Tell the Difference (With Pictures)

If you have crusty, cracked, crumbling, or discolored nails, it’s likely more than just a cosmetic problem. Nail fungus and nail psoriasis are two common causes of such nail changes. And they look pretty similar, which makes it hard to tell them apart. 

But they have different causes and treatments, so getting the right diagnosis is important. And to confuse matters even more, it’s possible to have both conditions at the same time.

What’s the difference between nail psoriasis and a fungal infection?

Nail psoriasis and nail fungus may look similar, but they’re caused by very different processes. 

Nail psoriasis

Psoriasis is an autoimmune condition that causes a thick, scaly skin rash that’s red or violet in color. Psoriasis happens because an overactive immune system causes skin cells to grow too fast. 

About half of people with psoriasis also have nail psoriasis. Just like in the skin, nail cells grow too fast. This causes specific changes in the look and structure of the nails. Some people with psoriasis and nail psoriasis can also have psoriatic arthritis, a type of psoriasis that affects the joints.

Psoriasis is never contagious — no matter where you have it on your body. 

Nail psoriasis is more than just a cosmetic issue. When you have nail psoriasis, you’re more likely to have:

• Psoriatic arthritis 

• More severe skin disease

• Finger pain or tenderness

• Difficulty with everyday tasks involving your hands and feet

• Feelings of embarrassment

Nail fungus (onychomycosis)

Nail fungus is a fungal infection of the nail. The medical term for it is onychomycosis. It happens when fungi, like molds and yeasts, grow in the space under your nail (your nail bed). Fungi feed off keratin, the main protein in your nails.

Unlike psoriasis, nail fungus is contagious. It can spread from one body part to another, and it can spread from one person to another. This can happen if your nail comes into contact with fungus from a skin infection somewhere else on your body or someone else’s body, like in athlete’s foot. You can also get a fungal infection from walking barefoot in a warm moist area like a locker room. 

Nail fungus isn’t part of a whole-body condition, like psoriasis. But it still causes symptoms. People with nail fungus can experience:

• Pain and discomfort

• Difficulty wearing certain shoes

• Embarrassment over nail appearance

Getting a diagnosis 

It can be tricky to figure out whether you have nail psoriasis or nail fungus. In most situations, it’s best to see your primary care provider or a dermatologist to get the right diagnosis and start the right treatment. 

To a trained eye, the diagnosis may be obvious after examining your nails and skin. But sometimes, it may be necessary to take and send nail clippings to a lab to check the diagnosis. 

Pictures of nail psoriasis vs. nail fungus

Because nail psoriasis and nail fungus are caused by different processes, they can cause distinct nail changes. And these specific changes can help tell them apart. These are easier to spot with a trained eye, but here are a few pointers and pictures to help you know what to look for. 

Nail psoriasis 

We’ll review five typical changes to look out for in nail psoriasis. Keep in mind that it’s possible to see more than one of these changes in the same nail. 

If nail psoriasis is mild, only one or two nails may be affected. When it’s more severe, nail psoriasis can affect all of your nails:  

1. Nail pitting: These look like tiny dents in the nail.   

2. Onycholysis: This is when part of the nail detaches from the nail bed, turning it white. It usually happens at the nail tip.

3. Discoloration: Nails can develop yellow, pink, or orange patches (called salmon patches or oil drops). Small, dark-red lines (splinter hemorrhages) may appear as well.

4. Nail thickening: This is due to the buildup of thick scale underneath the end of the nail. The medical term for this is subungual hyperkeratosis. 

5. Crumbly nails: This happens when nail psoriasis is very severe.

Nail fungus 

Nail fungus is most common in the toenails, but it can also affect fingernails. Most people have just one toenail involved. But, as the fungus spreads, it can involve the nearby toenails and even spread to the skin (athlete’s foot). 

Here arethree common changes from nail fungus to look for:

1. Discoloration: Nails can look yellow, green, brown, black, or white.

2. Nail thickening: This is the most common change. It can lead to broken and cracked nails.

3. Misshapen nails: Shortened or broken nails can happen with severe nail fungus.

Treating nail psoriasis and nail fungus

There are treatments for nail psoriasis and nail fungus. But it can take months or even a year to see results. So patience is key. And keep in mind that the treatments are different, so it’s important to get the right diagnosis. Here are the main treatments for each.

Nail psoriasis treatments

How you treat nail psoriasis depends on how severe it is. The best treatment for you also depends on whether you have psoriasis or psoriatic arthritis. 

Treating nail psoriasis usually involves one or more of these treatments:

• Topical medications: These are applied directly to the nail. They need to be applied regularly, usually once or twice a day. They can cause some irritation at or around the nail. Examples include tazarotene or a strong steroid. 

• Injections: These use a needle to inject steroids (or another medication) directly into or around the nail. A typical treatment course is usually 4 to 6 injections, 4 to 6 weeks apart. The procedure can be uncomfortable.

• Systemic treatment: This is medication that works throughout the body. These come as shots or pills. They’re the best option for more severe nail psoriasis, or psoriasis that also affects the skin and joints. Examples of this kind of psoriasis medication are etanercept, ustekinumab, and methotrexate.

• Laser treatment: This uses light to target blood vessels and control inflammation in psoriasis. Researchers are studying it as a treatment for nail psoriasis, but more research is needed.  

Nail fungus

There are a few different ways to treat nail fungus, but some are better than others. 

Here are some common options:

• Oral medications (pills): Medications like terbinafine and itraconazole work the best and fastest to treat nail fungus. But these medications come with the highest risk of side effects. And they can interact with other medications.

• Topical medications: These are treatments you apply directly to the nail. Examples include ciclopirox and efinaconazole. Side effects are pretty mild, like some redness around the nail.  

• Natural medications: There isn’t as much research on natural treatments yet, so it’s hard to say how effective these are. Options can include tea tree oil and Vicks VapoRub. 

• Nail removal: If other treatments don’t work, your primary care provider may recommend partial or complete removal of the nail plate. This can be done in the office with local numbing medicine. The nail will grow back, but it can take months. In some situations, permanent nail removal may be the best solution for you (like when the nail fungus keeps returning and causing symptoms). 

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Written by:

Maria Robinson, MD, MBA

Maria Robinson, MD, MBA, is a board-certified dermatologist and dermatopathologist who has practiced dermatology and dermatopathology for over 10 years across private practice, academic, and telehealth settings. She is a fellow of the American Academy of Dermatology and the American Society of Dermatopathology.

Edited by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. An experienced and dedicated pulmonologist and hospitalist, she spent a decade practicing and teaching clinical medicine at academic hospitals throughout London before transitioning to a career in health education and health technology.

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