What is the Difference Between Plaque Psoriasis and Psoriatic Arthritis?

Man itching his wrist.

Psoriasis is an autoimmune disorder that manifests as a chronic skin condition. Psoriasis can lead to the development of plaques, which are patches of scaly, red or white skin. Many individuals with psoriasis are later diagnosed with psoriatic arthritis, which is a condition with similar causes that results in joint pain, stiffness and swelling..

Both plaque psoriasis and psoriatic arthritis develop as a result of an autoimmune disorder, which is when the immune system attacks the body, leading to inflammation and/or pain. While psoriasis and skin symptoms typically develop before psoriatic arthritis, there are some cases in which arthritis develops months or even years before skin symptoms appear. In addition to a link to the immune system, doctors believe there is a link between more severe cases of psoriasis and the development of psoriatic arthritis. Additionally, many people with psoriatic arthritis have a parent or sibling with the disease. It most commonly occurs in adults between the ages of 30 and 50. 

The main differences between these conditions include location and lasting impact of symptoms. Even when an individual experiences skin plaques and arthritis as a result of psoriasis and psoriatic arthritis, they can take place in different locations. For example, an individual may have joint swelling in their feet as a result of psoriatic arthritis but will not see plaques develop in that area. Additionally, while psoriasis does not leave scarring or lasting harm, psoriatic arthritis can permanently damage joints, leaving them stiff or deformed. This is why it is important to discuss symptoms and concerns with your board-certified dermatologist to head off any lasting effects.

Understanding Psoriasis and Predisposition

While we know psoriasis is caused by the immune system, the exact cause is not known. The same can be said for psoriatic arthritis. Statistically, about 40 percent of people with psoriatic arthritis have relatives with psoriatic arthritis or with psoriasis, but scientists do not know what genes lead to these conditions. Ongoing research is investigating the causes of psoriasis and psoriatic arthritis in order to predict who may develop these conditions and to invent new treatments.

Psoriasis and Joint Pain

As a chronic autoimmune disorder, psoriasis can impact skin, joints and nails, and symptoms can vary from intermittent to chronic and from mild to debilitating. Symptoms develop as the immune system attacks the body, rather than protecting it from foreign intruders, which leads to inflammation. On the skin, this can manifest as sensitive, red patches and flaky skin. 

Although both psoriasis and psoriatic arthritis can cause joint pain, stiffness and swelling, the signs of psoriatic arthritis often resemble those of rheumatoid arthritis. Common psoriatic arthritis symptoms include:

  • Swollen fingers and toes which is often a precursor to significant joint symptoms
  • Foot pain, particularly at the back of your heel (Achilles tendinitis) or in the sole of your foot (plantar fasciitis)
  • Lower back pain called spondylitis which causes inflammation of the joints between your spinal vertebrae and in the joints between your pelvis and spine.

There are several different types of psoriatic arthritis that are identified based on how symptoms are affecting your body. For example, symmetric psoriatic arthritis affects both sides of the body (such as left and right knees) whereas asymmetric psoriatic arthritis only affects one side of the body. There are other types of psoriatic arthritis that are diagnosed based on the location of your inflammation. 

Skin Psoriasis Treatment Options and Medications

Every case of psoriasis is unique, and ultimately every treatment plan will be unique as well. While there is no known cure, the goal of psoriasis treatment is to reduce inflammation and control shedding of the skin to make flare-ups more manageable. It is important to contact your dermatologist right away if you develop joint pain, as psoriatic arthritis can cause severe joint damage if left untreated. 

Dermatology Associates of Plymouth Meeting offers a variety of treatment options to manage psoriasis and treat psoriatic arthritis symptoms: 

Topical Creams

Cortisone creams, ointments and lotions can help control psoriasis in many patients and should be used with specific instruction. These topical medications utilize steroids and have specific preparations depending on the location of the psoriasis. Other topical medications include:

  • Scalp treatment through non-prescription and prescription shampoos, oils and more, which contain coal tar, salicylic acid or cortisone
  • Retinoids, or prescription vitamin A-related gels

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Oral Medication

Oral medications such as methotrexate and cyclosporine are sometimes recommended when other treatments have failed.


Biologics are new injection treatments that are changing the way we treat psoriasis. There are multiple agents, which our doctors can review with you to discuss benefits and side effects.

Psoriatic Arthritis Treatment Options

Psoriatic arthritis symptoms can be treated with systemic drugs that affect your whole body. Depending on your unique case of psoriatic arthritis, your dermatologist may prescribe methotrexate, cyclosporine or certain biologics. In some cases, steroid injections can reduce inflammation quickly in an affected joint. At Dermatology Associates of Plymouth Meeting, we may team with a board-certified rheumatologist to treat joint disease linked to psoriatic arthritis. 

In addition to these medications or treatment options, whether you are experiencing psoriasis or psoriatic arthritis, your dermatologist may recommend lifestyle changes to help minimize symptoms and flare ups. We always encourage changes such as quitting smoking, drinking less and minimizing stressors which can help with psoriasis and psoriatic arthritis flare ups. With psoriasis and psoriatic arthritis, it is common for symptoms to come and go, but it is important to continue taking medication and undergoing treatments recommended by your dermatologist. 

If you are struggling to manage your plaque psoriasis or psoriatic arthritis, schedule an appointment today. Our team of board-certified dermatologists are experts in treating all types of psoriasis and can develop a personalized treatment plan based on your unique background and needs.