How to Tell the Difference Between Nail Psoriasis and Nail Fungus

While having a fresh manicure is the dream for most of us, sometimes your nail health can take a turn for the worse. For instance, your nails can begin to peel, crack, and turn discolored. Sure, nail polish can mask the appearance, but the underlying condition is still there. Nail psoriasis and nail fungus are usually to blame for these nail changes.

Nail fungus and nail psoriasis look pretty similar, making it hard to tell them apart. However, even though the conditions appear almost identical, there are some differences between them, including why they occur. Nail psoriasis is an autoimmune condition similar to the psoriasis patches you get on your skin. In contrast, nail fungus is a fungal infection that affects nails’ appearance and health.

Because differentiating between the two can be tricky, we spoke with two dermatologists to learn about the differences, causes, and treatment options for nail psoriasis and nail fungus.

Experts Featured in This Article

James Kilgour, MD, is a resident Stanford dermatologist and the founder of KilgourMD.

Neil Sadick, MD, is a dermatologist and a medical advisor for Maskād and Revivv.

What Is Nail Psoriasis?

“Nail psoriasis occurs when the same inflammatory process that affects the skin occurs within the nail matrix,” resident dermatologist James Kilgour, MD, tells PS. “The nail matrix is where the nail itself is formed, and when it becomes afflicted by psoriasis, it results in characteristic nail changes, which include pitting, oil spots, and onycholysis.”

Pitting looks like “multiple small pits in the surface of the nail”; oil spots are yellow-brown discolored patches on the nail; and onycholysis is lifting of the nail from the bed, he adds.

When you have nail psoriasis, your skin cells reproduce quickly. Anyone can get it, especially those over 40 years old and with a family history of psoriasis. “Psoriasis itself has a strong genetic component, so family history has a significant risk factor,” Dr. Kilgour says.

What Is Nail Fungus?

Nail fungus is a condition known as onychomycosis. It is an “infection of the nail caused by dermatophytes, which can also infect the skin, leading to a condition called tinea or ringworm,” Dr. Kilgour says. “It tends to more commonly affect the toenails, often alongside infection of the feet, known as tinea pedis.”

Nail Psoriasis vs. Fungus

Nail psoriasis and onychomycosis (nail fungus) are very similar in appearance, but there are slight differences. Nail fungus features thickening and discoloration of the nail, lifting of the nail from the bed, and scale and debris under the nail. With nail psoriasis, the surface of your nail will feel rough, thinning may occur, and your nail may have yellow or orange patches. Getting psoriasis under nails is less likely.

“It can be hard in some cases to tell the two apart, and that’s where the expertise of a dermatologist is needed,” Dr. Kilgour says. “That being said, isolated nail psoriasis is uncommon, and most will have other signs of psoriasis such as involvement of the skin and joints.”

Nail Psoriasis Treatment Options

Once you receive a physical exam from your dermatologist, they will “grade the severity based on their experience of seeing a wide range of psoriasis patients” and proceed with the treatment plan they believe will work best, Dr. Kilgour explains.

“The treatment options for nail psoriasis are topical injectable steroids, topical tacrolimus, corticosteroids, pimecrolimus, or any of the new anti-psoriasis cytokine inhibitors, either applied topically or injected,” dermatologist Neil Sadick, MD, says.

Vitamin D and retinoid creams, “as well as a multitude of systemic therapies, including both oral medications and biologic injectable medicines such as Skyrizi,” are also treatment options for nail psoriasis, Dr. Kilgour says.

Nail Fungus Treatment Options

If you have nail fungus, “the mainstay of treatment is with an antifungal,” Dr. Kilgour says. “While topical antifungal creams and nail polishes can be used, definitive treatment generally requires an oral antifungal course, typically taking three months.”

Our experts advise that oral antifungals require close monitoring by a dermatologist, often with lab monitoring, due to rare but potentially serious side effects. “Even with a three-month course of oral antifungals, recurrence rates for nail psoriasis are unfortunately high,” Dr. Kilgour says.

Keeping up with the appearance and health of your nails is ideal for preventing and treating nail fungus. You could consider “trimming of the nail and debriding of the nail plate.” This should be done by a doctor to ensure all the fungus is removed without causing any damage.

It can be exhausting to debate whether you have nail fungus or psoriasis. The best way to determine the cause of your nail issues is to speak with your doctor and set up a treatment plan.

Sydney Wingfield has been a freelance writer in the beauty and wellness space for six years. She has written for Women’s Health, Marie Claire, Glamour, and other publications and loves to cover all things skin care, makeup, and hair.