Living with psoriasis can be challenging as you work to manage unpleasant skin symptoms including itching, discoloration, bumps, flaky scales, and dry, cracked skin. Psoriatic arthritis (PsA), too, can be difficult as you contend with symptoms like achy joints, stiffness, and swelling. If you have one of these conditions, it’s only natural to worry that you may develop the other.

Psoriasis and PsA share genetic similarities and are considered common comorbidities — that is, conditions that can occur at the same time. Researchers have found that about one-third of people with psoriasis will eventually develop PsA. However, they are distinct conditions that can stand alone. PsA can develop years before psoriasis symptoms appear, or it may develop without psoriasis symptoms at all.

Read on to learn more about the relationship between psoriasis and PsA, including what scientists know about a person’s likelihood of developing both. Remember, too, that your health care provider is your best source for medical advice about psoriasis and PsA.

About Psoriatic Arthritis and Psoriasis

PsA and psoriasis are both autoimmune diseases, meaning they result from the immune system mistakenly attacking the body’s healthy tissues. Inflammation caused by the body’s overactive immune response leads to the symptoms characteristic of psoriasis and PsA.

Psoriasis is a chronic, inflammatory skin condition. In about 80 percent to 90 percent of cases, psoriasis is a scaly, itchy rash of skin plaques that most frequently affects the elbows, knees, and scalp.

PsA is characterized by inflammation of the tendons and ligaments. Symptoms of PsA include lower back pain, inflammatory joint pain, and joint swelling and stiffness. Often, PsA affects the nails, too, causing nail changes and symptoms such as pitting — small dents in your nails. Left untreated, PsA can cause lasting joint damage. Approximately 1 in 5 people with PsA will experience spinal inflammation, known as psoriatic spondylitis. In some instances, spinal inflammation is so severe that it can cause complete fusion of the vertebrae, known as ankylosing spondylitis.

The Relationship Between Psoriatic Arthritis and Psoriasis

Psoriasis is a risk factor for PsA. As noted, approximately 30 percent of people with psoriasis also develop PsA. Around 15 percent of people with PsA have no history of psoriasis before the onset of arthritis. The two are distinct chronic conditions, although they share a genetic connection. Psoriasis is an inflammatory and autoimmune skin disease. PsA is an inflammatory form of rheumatic disease or inflammatory arthritis.

The majority of PsA diagnoses are made in people who already have psoriasis. PsA usually starts 10 to 20 years after the onset of psoriasis, according to Johns Hopkins Arthritis Center. However, a person can develop PsA at any age, whether or not they have developed psoriasis. A MyPsoriasisTeam member shared, “I’ve suffered with psoriatic arthritis for as long as I’ve had psoriasis: 30 years (since I was 13 years old).”

But the two conditions don’t always occur together. “Everyone seems to have psoriasis along with psoriatic arthritis,” another MyPsoriasisTeam member said. “I just have psoriatic arthritis.”

Diagnosing PsA Without Psoriasis: Difficult but Doable

Diagnosing PsA, especially in the absence of psoriasis, can be challenging and contributes to delayed diagnosis and misdiagnosis. This difficulty stems from the fact that symptoms of other diseases can mimic those of PsA, including types of arthritis — like rheumatoid arthritis and osteoarthritis — as well as gout (a form of arthritis causing sudden, intense pain and swelling due to the buildup of uric acid crystals in the joints). Diagnosing PsA early and treating it promptly are important steps in helping prevent long-term, irreversible joint damage.

There is also a chance that a person diagnosed with either PsA or psoriasis has both conditions — but that one has gone undiagnosed or been misdiagnosed. Approximately 15 percent of people with psoriasis had PsA that had gone unrecognized or undiagnosed, according to a study published in the Journal of the American Academy of Dermatology.

There aren’t any definitive tests, such as blood tests, to diagnose PsA. However, a doctor can make a PsA diagnosis based on clinical signs and symptoms and by obtaining a medical history. You may need to visit a rheumatologist — a doctor who specializes in inflammatory conditions — for a definitive diagnosis of PsA. As part of the process, the doctor will likely ask if you or a family member have previously had a psoriatic disease like PsA or psoriasis. This factor can significantly increase your risk of developing PsA — 40 percent of people with the condition have a family history of psoriatic disease, according to MedlinePlus.

Talk With Others Who Understand

MyPsoriasisTeam is the social network for people with psoriatic disease and their loved ones. On MyPsoriasis Team, more than 123,000 members come together to ask questions, give advice, and share their experiences of life with psoriasis or PsA.

Do you have psoriasis, PsA, or both? Which came first? Share your experiences in a comment below or on your Activities page.