What Is Psoriasis? We Asked the Experts All the Questions You're Itching to Ask

Jennifer Larson
·7 min read

More than eight million people in the United States have the autoimmune skin condition known as psoriasis, according to the National Psoriasis Foundation. Psoriasis is a chronic condition. There’s no cure, but it can be managed—so if you're one of those people living with psoriasis (or know someone who is), what can you do about it? Here's everything you need to know.

What is Psoriasis?

Psoriasis, according to Cleveland Clinic, is a condition that occurs when the growth cycle of your skin cells accelerates far beyond a normal pace. It tends to first develop in young adults roughly between the ages of 15 and 35. A small percentage, around 10-15 percent, of people develop it before age 10, according to the National Psoriasis Foundation.

Cleveland Clinic Dermatologist Anthony Fernandez, MD, PhD, says psoriasis is a systemic disease, and psoriatic arthritis is one potential systemic aspect that can progress quickly.

How do you know if you have psoriasis?

“It’s almost always a skin rash,” says Mark Lebwohl, MD, a dermatologist in New York City and chair of the department of dermatology at the Icahn School of Medicine at Mount Sinai.

The most common type of psoriasis is plaque psoriasis. With this kind of psoriasis, you tend to develop salmon-pink or red patches or plaques with an overlying silvery scale. They appear in areas like the tops of the knees and elbows, scalp, behind the ears, and on your torso, says Susan Massick, MD, a dermatologist at The Ohio State University Wexner Medical Center.

In addition to plaque psoriasis, there are several other kinds of psoriasis:

  • Guttate psoriasis, which causes small, round or teardrop-shaped lesions or papules and often develops after an infection like strep throat

  • Inverse psoriasis, which tends to develop as red, inflamed skin in high-friction areas and can be triggered by a fungal infection

  • Nail psoriasis, which may cause small pits on the top of your nails, or thickened, crumbly nail beds that might mimic a fungal infection.

  • Pustular psoriasis, a less common type of psoriasis that shows up as pus-filled blisters

  • Erythrodermic psoriasis, a very uncommon type of psoriasis that causes a very painful red, peeling rash all over your body.

The symptoms vary, depending on what type of psoriasis you have. But most people think of those raised, red patches that are the hallmark of plaque psoriasis.

“Patches are generally mildly itchy, although itching can be severe in some,” says Dr. Massick.

It’s also possible to have more than one kind of psoriasis, says Lebwohl. You might start out with a case of plaque psoriasis and later develop another type.

What Causes Psoriasis?

Experts don’t know exactly what causes psoriasis, but they do know your body’s immune system is involved. Because psoriasis is an autoimmune disease, that means your body is essentially attacking itself. According to the American Academy of Dermatology, white blood cells called T-cells begin to attack your skin cells, which makes your body produce even more skin cells at a faster rate. Those skin cells begin to pile up and form scales or plaques.

Psoriasis tends to run in families. There seems to be a genetic component, but not everyone who develops psoriasis carries the genes that make someone more likely to develop it.  Some people only develop very mild cases, with very limited skin involvement, while others have plaques and scales over large parts of their bodies.

It’s not contagious, so you can’t “catch” it from someone else who has it. But certain factors can trigger a flare-up. Different people have different triggers, but the most common ones include:

  • Stress

  • Injury to your skin

  • Infections

  • Certain weather conditions, including cold, dry weather

  • Alcohol use

  • Smoking

  • Certain kinds of medications, such as prednisone, lithium and hydroxychloroquine.

Dermatologists typically suggest that you learn what your triggers are, so you can take steps to avoid them.

Related: Know the 5 Types of Psoriatic Arthritis

What’s the Difference Between Psoriasis and Psoriatic Arthritis?

Having psoriasis does raise your chances of developing certain other health conditions, which are called comorbidities. You’ll need to be vigilant about conditions like cardiovascular disease, type 2 diabetes, and an inflammatory disease of the eye called uveitis. You’re also at increased risk for developing depression.

One common comorbidity for psoriasis is psoriatic arthritis. When you have psoriatic arthritis, your body’s immune system attacks your joints.

“Approximately 30 percent of patients with psoriasis will develop psoriatic arthritis in their lifetime,” says Massick.

Usually, the psoriasis shows up first. But research suggest that 15-20 percent of patients may actually develop the arthritis first.

As with other forms of arthritis, psoriatic arthritis will make your joints feel swollen and painful. It might start with dactylitis, which is a swollen joint in a finger or toe. The swelling makes the entire digit look like a sausage, rigid and warm to the touch.  It can remain in these small joints, or it may progress to affect larger joints, like the knees, hips or elbows.

Related: What Does Psoriatic Arthritis Feel Like?

Massick routinely asks her psoriasis patients if they’re experiencing any stiffness in their joints, or if they’ve noticed any pain or swelling in particular areas. If you have psoriasis and you’ve noticed these kinds of symptoms, too, be sure to let your doctor know so they can examine you for signs of psoriatic arthritis. It might not be psoriatic arthritis–lots of people develop osteoarthritis, as they age–but it could be, and that could warrant a particular treatment.

How Do You Treat Psoriasis?

There’s no cure for psoriasis–or for psoriatic arthritis, either. But don’t get discouraged.  “We do have great treatments for both,” says Lebwohl.

Treatment depends on how severe your psoriasis is. A mild case or a case that doesn’t cover a very large area of skin might warrant just a topical treatment, or perhaps some phototherapy, according to Lebwohl.

Dr. Fernandez recommends using a moisturizing cream or ointment if you have either eczema or psoriasis. Keeping your skin moist is helpful because you’re more likely to itch if your skin is dry.

Some topical treatments that your doctor may recommend can include:

  • Topical corticosteroids

  • Synthetic Vitamin D creams

  • Calcineurin inhibitors

  • Topical retinoid creams

  • Anthralin cream

  • Salicylic acid

Some of these ointments and creams can be used for long periods of time, but others, like the calcineurin inhibitors, are only appropriate for short-term use. Topical corticosteroids are very commonly prescribed, but they can cause thinning of the skin, so your doctor might suggest you only use it during flare-ups.

But the more severe cases need more intensive treatment, especially if you also have psoriatic arthritis.

“I usually consider moving into the systemic medications if patients have moderate to severe psoriasis--significant skin involvement--and psoriatic arthritis,” says Massick.

For example, a biologic medication called a TNF alpha inhibitor might be a good option for treating your psoriatic disease. TNF alpha inhibitors are drugs that inhibit your body’s immune response to a protein produced by your white blood cells called tumor necrosis factor (TNF). If your body makes too much TNF, it can cause inflammation, so this category of meds works to stop that cycle of inflammation. These meds are given by injection or infusion.

Other drugs that are very effective have also come along, giving your doctor more options to offer you, depending on your diagnosis. For example, there are medications that target other kinds of proteins known as interleukins that cause inflammation. Another relatively new drug called a Janus kinase (JAK) inhibitor, was approved for the treatment of psoriatic arthritis in 2017, giving you the option of an oral medication.

Related: Can Stress Cause Arthritis?

When to See Your Doctor

Don’t wait to seek help if you think you are developing signs of psoriasis or psoriatic arthritis.

While many patients just have a mild case of psoriasis that can be easily controlled with topical treatments, Lebwohl sees other patients with much more severe cases. And the impact the disease has on their lives is profound.

“It interferes with everything they do,” he says. “It interferes with their jobs, it interferes with their education, it interferes with their day-to-day activities, it interferes with their intimacy, with their sex lives.”

That’s why he urges people to see their doctors sooner rather than later if they develop symptoms of psoriasis, so they can start looking for the best treatment to manage it.

Next, Does Cracking Your Knuckles Cause Arthritis?

Sources

  • Anthony Fernandez, MD, PhD and Cleveland Clinic Dermatologist

  • Susan Massick, MD, a dermatologist at The Ohio State University Wexner Medical Center

  • Mark Lebwohl, MD, a dermatologist in New York City and chair of the department of dermatology at the Icahn School of Medicine at Mount Sinai