A variety of medications exist to treat psoriasis. This is an autoimmune condition that affects the skin and other systems of the body. Some medications target psoriasis at a systemic level, while others primarily treat the skin symptoms.

Here, Dr. Joshua Zeichner explains the differences between systemic treatments and topical treatments, including examples of specific medications and potential side effects.

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There are a number of topical steroids available to manage symptoms of psoriasis.

Systemic treatments are medications that address psoriasis from the inside out. They treat the entire body rather than a specific area. A person may take these by mouth or receive them in the form of an injection.

Doctors tend to use systemic treatments when people have more severe psoriasis, as well as other related conditions, such as psoriatic arthritis. They may prescribe systemic treatments when the affected skin surface is too large for treatment with topical medications, or when plaques do not improve with topical treatments.

Systemic treatments may be more effective than topical treatments. They also carry more potential side effects, and some lower a person’s immunity. Although the risk is low, in some cases, these treatments may increase a person’s chance of developing an infection or cancer.

Topical medications treat the skin and do not address internal issues such as arthritis. They include creams, lotions, foams, solutions, gels, and tapes that people can apply directly to the skin. They only treat the areas of skin a person applies them to.

Topicals are excellent options for people with localized disease, such as when a person has plaques on the elbows or knees. They do not have as many side effects as systemic medications. However, they may not be as effective or practical in more severe cases of psoriasis.

Systemic treatments include traditional immune-suppressing medications as well as newer biologic agents.

Traditional systemic medications

These laboratory-made small molecules have relatively nonspecific effects in the body. Examples include:

  • Methotrexate and cyclosporine: These decrease immune system activity to block inflammation.
  • Acitretin: Rather than lowering immune activity, this vitamin A derivative normalizes skin cell turnover to prevent thick psoriasis plaques from developing.
  • Apremilast (Otezla): This is a small-molecule drug that has Food and Drug Administration (FDA) approval for the treatment of psoriasis. It seems to have more of an anti-inflammatory effect than an immunosuppressive effect.

Biologic treatments

Laboratories produce these medications using living organisms, such as bacteria. They are more specific than traditional drugs and do not generally suppress the immune system.

Four main classes of biologic medications have approval for treating psoriasis and psoriatic arthritis. They are classed based on how they work and which part of the immune system they address.

The four classes are:

The broad categories for topical treatments are steroidal and nonsteroidal.

Topical steroids

These creams, ointments, and other preparations have anti-inflammatory effects in the skin to clear psoriasis plaques. They include a class of medication called a corticosteroid.

Although effective and fast acting, topical steroids have potential side effects. For example, extended use can lead to thinning of the skin, dilated blood vessels, stretch marks, and pimples.

Doctors typically limit the use of topical steroids to no more than 2 consecutive weeks for most medications. After that initial treatment, they will usually recommend intermittent use of topical steroids for maintenance.

Nonsteroidal topical treatments

These medications use ingredients other than corticosteroids. They include:

  • Vitamin D analogs, such as calcipotriene and calcitriol: These seem to normalize skin cell turnover and calm inflammation.
  • Topical retinoids, such as tazarotene: These regulate the normal cell proliferation, or cell division, that contributes to the formation of psoriasis plaques.
  • Calcineurin inhibitors, such as tacrolimus ointment and pimecrolimus cream: These are not FDA approved for psoriasis, but many dermatologists do use them off-label to treat this condition.

Nonsteroidal topicals do not tend to be as potent or fast acting as steroidal creams, but they are safe to use for extended periods of time. They are commonly part of a maintenance regimen, along with topical steroids.

People with moderate-to-severe psoriasis commonly use systemic and topical treatments together. Although systemic medications are effective, people may not achieve as much skin clearance as they would like.

For example, psoriasis plaques may be much better but not completely clear, or some plaques may not respond at all. In these cases, people can use directed topical treatments alongside systemic treatments.

A doctor may recommend systemic treatments if psoriasis is severe, if it affects a large body surface, if previous topicals were not effective, or if there are systemic manifestations, such as arthritis.

Topical treatments typically treat plaques on specific areas, such as the elbows or knees. They do not cause as many side effects as systemic treatments, but they may not be as effective in more severe cases of psoriasis.

Systemic treatments have potential side effects for the entire body, including a risk of infections or cancer. Certain medications may cause nausea or skin reactions at the site of injection.

Topical treatments are associated with side effects in the specific treated areas. These side effects include thinning of the skin, stretch marks, dilated blood vessels, and pimples.

Dermatologists regularly use skin exams and blood work to monitor people taking systemic medications. They may recommend temporarily stopping a systemic medication if it causes certain side effects.

For people using topical medications, dermatologists regularly evaluate the skin for side effects. A person should stop using a topical right away if it causes thinning of the skin.

It is important to treat psoriatic arthritis at its earliest stages to prevent complications. Joint destruction due to psoriatic arthritis is permanent.

Psoriasis skin lesions are treatable regardless of how long they are present. Severe plaques commonly heal with dark or red spots known as post-inflammatory pigmentation, or post-inflammatory erythema, but this will improve on its own over weeks to months.

Psoriasis is associated with metabolic syndrome, including heart disease and diabetes. Eating a well-balanced diet that is rich in fresh fish, colorful fruit, and green leafy vegetables provides the body with the vitamins and nutrients it needs to function at its best.

A low fat diet is important for people who have high cholesterol. A diet low in sugary food benefits people who have diabetes or prediabetes. Doctors may recommend weight loss for people who have overweight or obesity.

Finally, smoking is a known factor that can worsen psoriasis. It is especially important for people with psoriasis to quit smoking.

A flood of new topical and systemic medications can treat psoriasis. However, it is important to visit a dermatologist for proper diagnosis and treatment.

The future may bring genetic testing options to understand the specific causes of psoriasis and determine effective personalized treatments.

People with psoriasis should speak to a doctor about their personal preferences and beliefs. It is important to navigate psoriasis treatments together.

A person should consider getting another opinion if a doctor only prescribes topical medications that do not work, or if a doctor does not use biologic medications.

Patients are consumers of healthcare. It is important for people to seek out different opinions for care options and be their own advocates.

Dr. Joshua Zeichner is a board certified dermatologist on full-time faculty at the Mount Sinai Hospital in New York City, NY. He received his medical degree from the Johns Hopkins University School of Medicine, followed by residency and fellowship in Dermatology at the Mount Sinai Hospital Department of Dermatology. He is a fellow of the American Academy of Dermatology.