Can You Have Psoriatic Arthritis Without Psoriasis?

Experts in psoriatic arthritis have long faced a chicken-and-the-egg-like question: Can you have psoriatic arthritis without having psoriasis first? Some say yes, while others say no. And some say yes and no.

"There is a lot of debate going on," Ted Mikuls, MD, professor of internal medicine in the division of rheumatology at the University of Nebraska Medical Center, told Health.

Here's what you should know about psoriasis and psoriatic arthritis, including their risk factors and the importance of getting a correct diagnosis.

What Are Psoriatic Arthritis and Psoriasis?

Psoriatic arthritis and psoriasis are autoimmune diseases, meaning the immune system mistakenly targets and attacks its healthy cells.

The immune system attacks the skin with psoriasis, leading to the telltale raised red or silvery patches. And psoriatic arthritis attacks the joints, causing stiffness, pain, and swelling.

About 20% of people with psoriasis develop psoriatic arthritis. So, having psoriasis doesn't mean you'll develop psoriatic arthritis. At the same time, there usually aren't signs of if or when someone with psoriasis will also have psoriatic arthritis.

But the question remains: If you first experience the joint symptoms of psoriatic arthritis, does that mean you don't have psoriasis? Or does that mean that you haven't yet detected psoriasis?

Psoriasis Risk Factors

Psoriasis usually appears between ages 15–25, but the condition can develop at any age.

Also, genetics is one of the biggest risk factors for getting psoriasis. A gene called psoriasis susceptibility 1 (PSORS1) makes you more likely to develop psoriasis and links to the early onset and severity. Another gene called human leukocyte antigen B27 (HLA B27) also links to psoriasis and psoriatic arthritis.

Additional risk factors that can trigger or make psoriasis worse include:

• Injury to the skin
• Stress
• Illness
• Infection
• Weather
• Smoking and alcohol use
• Allergies to certain foods or environmental factors

Psoriatic Arthritis Risk Factors

The risk factors for psoriatic arthritis are not as clear as psoriasis. However, psoriatic arthritis typically appears between ages 30–50. Still, like psoriasis, the condition can develop at any age.

Additionally, there is some genetic factor. If you have a family history of the disease, you are more likely to develop it. In fact, one study published in 2016 in Arthritis & Rheumatology found that 33% to 50% of people with psoriatic arthritis have a first-degree relative with the condition.

Diagnosing Psoriasis

Existing psoriasis might be largely invisible, such as hiding in your belly button or behind your ears. 

"Certainly, it is at least partly a detection issue," said Dr. Mikuls. "Skin psoriasis can be very, very subtle and appear in places we don't look at closely."

But you also can't rule out the possibility that psoriatic arthritis can occur without psoriasis, noted Dr. Mikuls. About 10% to 15% of people with psoriasis have psoriatic arthritis that they simply have not yet detected.

Another thing to consider is that people who have both psoriasis and psoriatic arthritis don't necessarily have the same degree of symptoms. Your psoriasis can be mild, while another person's arthritis is severe.

"There can be a real disconnect between the severity of your skin involvement and your arthritis," added Dr. Mikuls.

The Importance of a Correct Diagnosis

As of December 2022, more research is needed to fully understand whether you can have psoriatic arthritis without any psoriasis. But speaking to a healthcare provider if you're experiencing symptoms of either condition is critical for your treatment.

"In the past, we would have said treatments [for different types of arthritis] overlap," explained Dr. Mikuls. "But more and more, we're learning that [treatments] really are uniquely different in many ways."

In other words, not all cases of psoriatic arthritis are the same, nor do all treatments work the same way for everyone. 

Take disease-modifying antirheumatic drugs DMARDs (DMARDs), for example. DMARDs are a psoriatic arthritis treatment that could also work for other forms of arthritis, explained Dr. Mikuls. But other treatments, like biologics, may work for psoriatic arthritis but not other forms of arthritis like rheumatoid arthritis.

"The lesson learned in rheumatology is that patients don't always present the same way," added Dr. Mikuls.

A Quick Review

Psoriasis and psoriatic arthritis are autoimmune diseases that cause inflammation. Psoriasis causes skin inflammation and can happen early in life. In contrast, psoriatic arthritis causes inflammation of the joints and tends to happen later in life. 

With both conditions, having a family history increases your risk of developing the same condition. Only about one-third of people with psoriasis develop psoriatic arthritis. So, it's possible to have psoriatic arthritis without having psoriasis.