Psoriatic Arthritis Rash: Pictures, Symptoms, and Treatment Options

Many people with psoriatic arthritis also have psoriasis, a type of skin rash. For most people, the skin rash starts 5 to 12 years before having any joint symptoms. But for others, skin changes can happen at the same time — or even after — arthritis develops.

There are a few different types of psoriasis rashes. Each type looks a little different and can affect different parts of the body. In some people, psoriasis affects the nails, causing them to be thick and brittle. No matter what type you have, psoriasis can hurt, itch, and even bleed when you scratch it. 

Read on to learn about the different types of psoriasis and the treatment options available. 

What does a psoriatic arthritis rash look like?

Here we’ll review the five main psoriasis types — from most to least common. Keep in mind that it’s possible to have more than one type of psoriasis at a time. 

1. Plaque psoriasis

You can get plaque psoriasis anywhere, but it usually affects: 

• Elbows

• Knees

• Scalp

Plaque psoriasis forms patches of raised skin that are pink, red, or violet in color, depending on your underlying skin tone. The patches may be covered by a thick white or silver scale. The spots can be small (like the size of a dime) or quite large (bigger than the size of your hand).

Plaque psoriasis forms patches of raised skin on the legs.

Plaque psoriasis patches are covered by a thick white scale.

2. Inverse psoriasis

Inverse psoriasis affects skin folds, for example: 

• Armpits

• Groin

• In between the buttocks

• Under the breasts 

Inverse psoriasis forms moist, red, violet, or brown patches of skin that may not have a lot of scale. This type of psoriasis can be misdiagnosed as a skin infection, which can also cause red patches of skin. One difference is that skin infections can have more scale or yellow crust compared to inverse psoriasis. You may need to see a dermatologist to know which one you have.

Inverse psoriasis can form in skin folds, such as in the armpit.

Inverse psoriasis forms under the breasts.

3. Guttate psoriasis

Guttate psoriasis usually affects people under the age of 30. This type of psoriasis affects the:

• Torso 

• Arms

• Legs

Guttate psoriasis forms pink, red, white, violet, or brown patches the size of a coin or smaller. The spots can have fine white scales on top. This type of psoriasis can happen after certain infections, such as strep throat.

Guttate psoriasis forms small patches with fine scales.

A guttate psoriasis rash covers a person’s back.

4. Pustular psoriasis

Pustular psoriasis looks like small pus-filled bumps, each about the size of a pencil eraser. The bumps are usually surrounded by red or violet skin, and they can be pretty painful. Sometimes the bumps grow together, forming large areas that can shed skin. 

Pustular psoriasis can involve different parts of the body, including the palms of the hands and soles of the feet.

Pustular psoriasis forms small bumps on the skin.

Pustular psoriasis forms on the sole of the foot.

5. Erythrodermic psoriasis

Erythrodermic psoriasis is rare and can be life-threatening. It causes severe skin rash and shedding, and can affect large portions of skin at once. People with this type of psoriasis can have other symptoms, like fever and chills. This type of rash can be an emergency, so it’s important to reach out to a healthcare professional or emergency services if you develop these symptoms. 

What causes a psoriatic arthritis rash?

Scientists aren’t exactly sure what causes psoriasis. So far, research shows that it’s likely a combination of different things, like your genes and an overactive immune system. 

But irrespective of the underlying cause, people with psoriatic arthritis and psoriasis may notice triggers that worsen their rash. Psoriasis affects everyone differently, but here are some common triggers:

• Certain medications, like beta blockers (for example, metoprolol or propranolol) and nonsteroidal anti-inflammatory drugs (NSAIDS, like naproxen)

• Some foods, like sugar and alcohol

• Smoking

• Stress

• Certain illnesses, like strep throat or the flu

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• Common triggers: From medications to certain foods, lots of things can make your psoriasis worse.

How long does a psoriatic arthritis rash last?

Psoriasis usually doesn’t go away on its own, but treatment can help to control it and keep your skin clear. You may need to try different psoriasis treatments to find one that works for you. Keep in mind that some treatments for psoriatic arthritis will also help clear your psoriasis.

If you stop your psoriasis treatment, you may have a period where your skin stays clear (called a “remission”). But your psoriasis may also go back to the way it was before stopping treatment — or it may even get worse. 

It’s hard to predict what will happen if you stop treating your psoriasis since everyone’s experience is different. So talk with your dermatologist or other healthcare professional before coming off treatment.

How is a psoriatic rash diagnosed?

Dermatologists and some other healthcare professionals may be able to diagnose psoriasis just by looking at the rash. In cases when it’s not clear, a skin biopsy (a minor procedure performed in the office) may be done. 

Rheumatologists usually diagnose psoriatic arthritis based on your symptoms and physical exam (like how your joints look and move). They may also use additional tests, like an X-ray or ultrasound. 

How do you treat a psoriatic arthritis rash?

There are many effective treatments for psoriasis. Some are prescription creams (called topical medications) that you apply directly to the skin rash. 

There are also medications that act inside the body — like pills, injections, and infusions. As mentioned above, some psoriatic arthritis treatments also work well to treat psoriasis. So if you have both conditions, it’s possible you’ll only need one treatment.

Let’s run through the main types of prescription treatments for skin psoriasis.

Topical medications

These include medications you put directly on your skin, like creams, lotions, and ointments. You may use them alone or in combination with other treatments. 

• Corticosteroids: These lower inflammation, redness, and itching. Some examples include triamcinolone, mometasone, and halobetasol. If you have very mild psoriasis, hydrocortisone is available over the counter.

• Calcineurin inhibitors: These lower the immune system response in the skin. Examples include tacrolimus and pimecrolimus.

• Vitamin D analogues: These are similar to vitamin D, and they help decrease skin growth. Examples are calcitriol and calcipotriene.

• Topical retinoids: Tazarotene and other topical retinoids can decrease nail thickness and help it regrow normally.  

Oral medications and biologics 

If you have more severe psoriasis or psoriatic arthritis, you may need treatment with stronger medications that you take by mouth or by injection. Here are some common options:

• Oral medications: These include medications that lower or alter your immune response, like methotrexate, cyclosporine (Sandimmune), and apremilast (Otezla). Acitretin (Soriatane) is a different type of medication you take by mouth. It helps restore normal skin growth.

• Biologics: These are medications that are injected or infused into your body. Biologics work by targeting specific parts of the immune system. Examples include adalimumab (Humira), infliximab (Remicade), and ustekinumab (Stelara).

Phototherapy

Phototherapy is a treatment for when you have a lot of psoriasis. It uses specific wavelengths of ultraviolet (UV) light to treat psoriasis. Treatments usually take place at the doctor’s office, but it’s possible to have a phototherapy unit at home. The main types are: 

• Narrowband ultraviolet B (NBUVB): This is the most common type of phototherapy used for psoriasis. 

• Psoralen and ultraviolet A (PUVA): This uses light in combination with psoralen, an oral medication that makes the skin more sensitive to light.

• Excimer laser: This is a small, handheld laser that you can use for small areas.

Home remedies

If you have psoriatic arthritis and psoriasis, take these steps to help improve your skin:

• Keep your skin hydrated by moisturizing often. 

• Minimize skin irritation by avoiding harsh soaps, very hot water in your shower, and picking at your skin.

• Soak in a lukewarm bath with colloidal oatmeal for 15 minutes. 

• Use your medications as directed. 

• Learn your triggers and avoid them. 

• Expose your skin to natural sunlight. Make sure you don’t burn — try for just 5 to 10 minutes a day. 

• Use mindful walking, meditation, or breathing techniques to lower stress in your life. 

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Written by:

Maria Robinson, MD, MBA

Maria Robinson, MD, MBA, is a board-certified dermatologist and dermatopathologist who has practiced dermatology and dermatopathology for over 10 years across private practice, academic, and telehealth settings. She is a fellow of the American Academy of Dermatology and the American Society of Dermatopathology.

Edited by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. An experienced and dedicated pulmonologist and hospitalist, she spent a decade practicing and teaching clinical medicine at academic hospitals throughout London before transitioning to a career in health education and health technology.

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