Psoriatic arthritis is a form of arthritis that typically occurs in people with psoriasis. In addition to pain, stiffness, and swelling of the joints, psoriatic arthritis can cause a red, scaly rash.
In this article, we discuss whether psoriatic arthritis (PsA) always causes a rash. We also cover symptoms, treatment, and home remedies for a psoriatic rash.
There is a close link between PsA and psoriasis.
Psoriasis is a common skin condition that affects around 3 percent of people in the United States. It occurs when the body replaces skin cells too quickly, which can result in a red, scaly rash developing on the skin.
Doctors do not fully understand what causes psoriasis, but they believe that it occurs due to a problem with the immune system.
However, not everyone with PsA has the characteristic psoriasis rash. According to a 2014 review, approximately 10 to 37 percent of people with PsA experience skin and joint symptoms at the same time, while around 6 to 18 percent of individuals have symptoms in their joints before a psoriatic rash appears.
The authors of a more recent review state that around 80 percent of people with PsA experience symptoms of psoriasis before they develop joint inflammation.
The psoriatic rash typically presents as thick, red patches of skin with a covering of silvery scales. These patches can be dry, itchy, and sore. The rash can develop anywhere, but it often affects the following parts of the body:
- lower back
- soles of feet
There are various types of psoriasis, each of which can cause a slightly different rash. It is possible to have more than one type of psoriasis at the same time. Some common types of psoriasis include the following:
- Plaque psoriasis is the most common form, affecting around 85 to 90 percent of people with psoriasis. This type of psoriasis causes red, dry patches of skin with silvery scales covering them. These plaques can vary in both size and shape.
- Guttate psoriasis causes many small, oval-shaped patches that usually appear on the chest, upper arms, thighs, and scalp.
- Inverse psoriasis causes smooth, red patches that form in areas where the skin folds, such as around the genitals, breasts, and armpits. Friction and sweating can make these patches worse.
- Pustular psoriasis is a rarer form of psoriasis that causes small, fluid-filled blisters, known as pustules, to develop on the skin.
- Erythrodermic psoriasis is a rare and severe form of psoriasis that affects most of a person’s body. It causes red, scaly skin, and some people experience intense itching or burning. This type of psoriasis requires immediate treatment.
Many different treatments are available for people with a psoriatic rash. The choice of treatment will depend on the type and severity of the rash. Different people respond to different medications, and some people may require a combination of treatments.
Treatment options for a psoriatic rash include:
Doctors usually recommend topical treatments for mild or moderate psoriasis. These may include the following:
- Emollients are non-cosmetic moisturizers that help protect the skin and reduce dryness, itching, and scaling.
- Topical steroids vary in strength, and stronger topical steroids require a prescription. These creams and ointments work by reducing inflammation and slowing skin cell growth.
- Vitamin-D analogs work by slowing skin cell growth, and they can help remove scales and flatten thick plaques. Doctors often prescribe these in combination with topical steroids.
- Topical retinoids are a synthetic form of vitamin A, and doctors often prescribe them in combination with topical steroids. Retinoids help slow skin cell growth, decrease scaling, and reduce thick skin patches. Women who are pregnant should avoid retinoids.
- Coal tar comes in the form of shampoos, foams, and ointments, which are available over the counter. These medications can help reduce itching and scales.
- Calcineurin inhibitors include tacrolimus ointment and pimecrolimus cream. Doctors sometimes prescribe these medications to treat psoriasis, particularly plaque psoriasis on the face or inverse psoriasis.
Also known as phototherapy, light therapy uses ultraviolet (UV) light to treat a person’s skin. Light therapy usually takes place in a hospital or a special center, and a person may need two to three sessions a week for it to be effective.
Doctors often prescribe light therapy in combination with some topical treatments.
Light therapy can be beneficial for people with:
- nail psoriasis
- psoriasis on the palms of the hands and the soles of the feet
- scalp psoriasis
- thick plaques
- large areas of psoriasis
Different types of light therapy are available, including:
- Ultraviolet B (UVB) therapy. UVB therapy requires a person to stand in a light box and receive a dose of invisible light.
- Laser treatment. A doctor delivers high doses of light directly to the affected areas of a person’s skin.
- Psoralen plus ultraviolet A (PUVA). For this treatment, a person either takes a psoralen tablet or soaks in a bath containing psoralen. This chemical makes the skin more sensitive to UV light.
- At-home treatment. The individual uses a light box or handheld device at home.
Light therapy is a good option for people who cannot use other forms of psoriasis treatment. These people may include:
- pregnant and breastfeeding women
- people with a weakened immune system or an infection
Doctors do not recommend light therapy for people who:
- have or have had skin cancer
- have medical conditions that make them sensitive to UV light, including lupus and porphyria
- are taking medications that can increase their sensitivity to UV light, including certain antibiotics, diuretics, and antifungals
Topical treatments can help manage symptoms, but they do not resolve the underlying problem of psoriasis or psoriatic arthritis. Long-term options, such as biologic drugs, may do this.
Guidelines published in 2018 recommend the use of biologic therapy as a first-line treatment for people with a new diagnosis of psoriatic arthritis.
These drugs are proving effective at reducing the frequency of flares, the severity of symptoms, and slowing the progression of the disease.
However, they can have serious, adverse effects and may not be suitable for everyone. In these cases, other long-term options are available.
A doctor will help an individual make a suitable choice.
People with PsA can try using home remedies and lifestyle changes to help treat or prevent a psoriatic rash. These include:
- Taking warm baths and showers rather than hot ones. Avoiding extremes temperatures can help prevent skin dryness.
- Using emollients to prevent dry skin.
- Avoiding cosmetics and fragrances that aggravate the skin, such as strong perfumes. Use sulfite-free and paraben-free shampoos, conditioners, and soaps instead.
- Eating a healthful and balanced diet that includes plenty of vitamins, minerals, and omega-3 fatty acids. Research suggests that omega-3s may help reduce inflammation.
In addition to joint inflammation, many people with PsA also experience a psoriatic rash. This rash is typically red and scaly, but its type and severity can vary considerably.
Treatments for a psoriatic rash include topical creams and ointments, light therapy, and systemic medications. A doctor will typically begin by prescribing milder topical treatments and seeing how a person’s symptoms respond. Some home remedies can also help reduce or prevent symptoms of psoriasis.