New Psoriasis Guidelines May Finally Get You the Right Treatment

A new, simplified method of grading psoriasis severity proves that when it comes to treating chronic skin conditions one size does not fit all.

by Claire Gillespie Health Writer

Editor's Note: This story is part of a new series on HealthCentral called "Get Your Ph.D.!", which is geared toward people who've got the basics of their condition down and want to up their expertise. Who's ready to go pro?!

As a chronic autoimmune skin condition, psoriasis can have a huge physical and emotional impact on a person’s life—especially if you’ve been living with it for several years. Inflamed, itchy, scaly patches of skin, which often go hand-in-hand with bleeding, pain, anxiety and stiff, swollen joints, are no party. By this point, you’ve probably tried a bunch of different treatments to get things under control. But what if, unbeknownst to you, you haven’t had access to the most effective treatment for your symptoms?

That could be about to change.

A consortium of more than 100 of the world’s top derms, led by the International Psoriasis Council (IPC), a St. Louis, Missouri-based nonprofit organization dedicated to improving patient care around the world, have put their heads together and figured out a new, simplified method of classifying psoriasis severity. This isn’t just to make their own jobs easier. The goal is to help people with psoriasis get the best course of treatment, which can often be difficult. Up until now, the measures used in routine practice under-classify psoriasis severity, wrote the authors of a consensus statement published in the Journal of the American Academy of Dermatology. Anyone with the condition knows that there’s no “one size fits all” therapy, and that it can take a fair amount of trial and error to determine what treatment path is going to be most effective.

How the Old Psoriasis Classification Worked

Previously, the main approaches to determining psoriasis severity (and therefore treatment) were based on the percentage of body surface area (BSA) affected and/or the Psoriasis Area Severity Index (PASI).

Under BSA methodology:

  • mild psoriasis means less than 3% of the body is affected

  • moderate psoriasis means 3% to 10% of the body is affected

  • severe psoriasis means more than 10% of the body is affected

PASI looks at:

  • the body area of the disease

  • the intensity of any redness and scaling

  • plaque thickness

Unfortunately, both methods were inherently flawed, say the IPC members in their consensus statement. These methods didn’t, as a matter of course, consider the impact of psoriasis on certain “special” parts of the body, like the face, scalp, genitals, hands, feet or nails. While it’s not news to anyone who has worked to manage their psoriasis for years, the council found that having psoriasis on a small area of skin can still have a huge impact.

“To give you an idea, 1% BSA is the size of your palm,” explains Robin Lewallen, M.D., a dermatologist specializing in psoriasis at Newport Beach Dermatology and Plastic Surgery in Newport Beach, California. “Imagine having 2% BSA involvement of your face or soles of your feet. The psychological impact of facial involvement or the physical impact on your ability to walk could certainly be severe despite not meeting the prior guidelines’ definition.

"In many cases, insurance denies or requires prior authorization for systemic medications (advanced treatments that affect the whole body, like phototherapy or injectable biologic drugs) in patients that are not ‘severe.’” The question then was, should it be up to each individual psoriasis patient to decide whether their condition was severe or not, based on how it impacted their life?

Another flaw of the old approach was that it didn’t look at how each individual patient had responded to previous topical treatments. Essentially, a patient could be unresponsive to topical treatments, but still not qualify for more advanced therapies, because less than 10% of their body was affected. “The new method is more simplistic and inclusive,” Dr. Lewallen says. “It takes into account the patient's history of treatment as well as the location and extent of involvement.”

This means patients who have tried and failed topical therapy would be considered as candidates for systemic therapy. Plus, patients with psoriasis on “special sites,” such as the face, palms, soles, genitalia, and scalp wouldn’t be ruled out.

The new IPC method discards the mild, moderate, and severe labels altogether, and uses three well-defined criteria. For a patient to qualify for systemic therapy, at least one of the following must be true:

  1. They have psoriasis lesions on 10% or more of their body surface, or...

  2. They have psoriasis lesions of any size on sensitive areas of the body (i.e. their hands/feet, face, genitals or scalp), or...

  3. Topical therapy failed to control their symptoms.

“The old system was designed primarily for researchers and drug studies and was not very useful to the average dermatologist,” explains Dale Kooistra M.D., a dermatologist affiliated with Palomar Medical Center Poway in Poway, CA. “It didn’t consider all the ways psoriasis affects people. Having psoriasis on the face, hands, or genital areas are socially much worse than having a similar size plaque on the back that is not seen. The new method will be better because it will include patients for systemic therapy with ‘disabling’ psoriasis that did not meet the older criteria.”

What’s Best for You: Topical or Systemic?

Topical therapies, typically the first line of defense, are treatments applied directly to affected areas of the skin, such as topical steroids, topical vitamin D, topical retinoids, and tars. It's very likely that you've tried at least one of these. They can relieve pain and itching, reduce inflammation or slow down the high rate of cell growth (aka plaques) seen in psoriasis. “Topical therapy is best suited for patients with mild symptoms or those with limited skin involvement in areas that do not affect a patient's activities of daily living,” Dr. Lewallen says.

Phototherapy, which treats patients’ skin with a very small, controlled amount of ultraviolet light several times a week, falls somewhere in between topical and systemic therapies. It may be used in conjunction with psoralens, a light-sensitive oral or topical med that attracts and absorbs UV light.

If topical treatments don’t work, and phototherapy is ruled out (for instance, if you are at a particularly high risk of skin cancer), your doctor may suggest systemic medications. These are prescription drugs (some are taken orally, some are injected) that work throughout the body, like immunosuppressive medications and biological medications. Again, different drugs work for different people. But Dr. Lewallen says that in general, good candidates for a systemic medication are those with extensive disease (i.e. more involvement than is practical to apply topical medication to), those for whom topical therapy has failed, or those with psoriasis involving a “special site’ that may affect daily life.

No matter which parts of your body are affected by psoriasis, the new method of classifying severity may open the door to different—and potentially more effective—treatment options.

PsO Treatment Categorization: Journal of the American Academy of Dermatology. (2019). "Recategorization of psoriasis severity: Delphi consensus from the International Psoriasis Council." jaad.org

Claire Gillespie
Meet Our Writer
Claire Gillespie

Claire Gillespie writes about mental health, psoriasis, psoriatic arthritis and IBS for HealthCentral. She is a passionate about mental health awareness, and also writes about health and wellness for other sites, including Vice, SELF, Zocdoc, Reader’s Digest, and Healthline. You can follow her on Twitter @southpawclaire.