Plaque Psoriasis Treatment Strategies
Sylvia Hsu, MD
Hospital and Institutional Affiliations
Temple University School of Medicine
Numerous considerations must be made when navigating the initial decision to prescribe topical vs systemic therapy for patients with plaque psoriasis. Typically, if a patient has mild psoriasis, we usually start treatment with a topical steroid. Mild psoriasis is defined as ≤3% body surface area (BSA) involvement, with the size of a patient’s hand being considered 1% BSA for reference. When a patient has 3% to 10% BSA involvement, this is considered to be moderate psoriasis. More than 10% BSA involvement is considered severe psoriasis.
There are some notable exceptions. If a patient can’t perform their daily functions or walk because the psoriasis is on their hands and feet, their psoriasis can be classified as severe. Involvement of the genitalia can also change the severity because that can affect their social life or relationships. We can upgrade disease severity classification depending on what part of the body is affected and how significantly the psoriasis affects a patient’s daily function; however, percentage of BSA is used by definition.
If a patient has very localized psoriasis — perhaps they just have psoriasis on their elbows, knees, or scalp — we would typically start treatment with a topical steroid. We would consider systemic treatment when patients have psoriasis that is beyond what can be handled with a topical agent. Sometimes patients have plaques all over their body, so it would be impractical for them to be spending hours a day applying a topical ointment on their whole body twice daily.
I usually do not start with the biologic that requires intravenous administration. I used to give this biologic years ago, but now we have 10 other biologic options that can be administered subcutaneously that I would choose first.
If insurance coverage were not an issue, I would choose a drug that blocks the pathway involving type 17 helper T cells (TH-17). More than a decade ago, it was thought that psoriasis was a TH-1 disease. We now know that it is more of a TH-17 pathway disease. So I would pick a drug that blocks that TH-17 pathway first. In addition, the most recently available biologic drugs are interleukin (IL)-23 inhibitors. So, as IL-23 drives the TH-17 pathway, an IL-23 inhibitor is very a good treatment option.
I like to explain the treatment timeline to each patient, in particular discussing how long it is going to take for the medication to achieve its full effect.
When it comes to addressing adherence to systemic therapy, I think that most people adhere to regimens because they see that they are getting better. One thing that would contribute to nonadherence is if the drug isn’t working that well or if patients are experiencing side effects. For example, I saw a patient today who had been prescribed apremilast for his psoriasis who later decided to stop taking it because of the side effects. He was experiencing diarrhea and believed treatment wasn’t working very well because apremilast takes a few months for its full effect. However, if a patient is on a biologic that works well, I think that typically they are adherent to treatment because they see the benefits of using it. Adherence to treatment with topical steroids may be difficult because usually we’ll prescribe an ointment for the body, and ointments can be messy, so I can see why patients may not always adhere to therapy.
Dermatologists should be more aggressive in treating psoriasis because some studies have shown that more aggressive treatment can decrease overall inflammation. In fact, there are studies that indicate that treatment of systemic inflammation can potentially decrease the risk for cardiovascular events.2 So there is evidence that it may be better to be more aggressive when treating psoriasis, rather than just giving a topical steroid when the patient could benefit from systemic therapy. I see patients who have seen other dermatologists, and all they were given was a topical ssteroid. I believe many dermatologists shy away from biologics, perhaps because biologics weren’t available when they were in training or they weren’t trained on using them during their residency.
Dermatologists should also make sure that they get the patient’s primary care physician involved in patient care. Patients with psoriasis really need to be assessed for other comorbidities such as obesity, diabetes, hyperlipidemia, and hypertension.
Sylvia Hsu, MD, is chair of dermatology at Temple University School of Medicine, in Philadelphia, Pennsylvania. Dr. Hsu was president of the Houston Dermatological Society and she was a member of the Editorial Board for the Journal of the Academy of Dermatology. She is a member of the Advisory Board for Dermatology World and an emeritus member of the Medical Board of the National Psoriasis Foundation.
1.Gisondi P, Fostini AC, Fossà I, Girolomoni G, Targher G. Psoriasis and the metabolic syndrome. Clin Dermatol. 2018;36(1):21-28.
2. Ridker PM, Everett BM, Thuren T, et al. Antiinflammatory therapy with canakinumab for atherosclerotic disease. N Engl J Med. 2017;377(12):1119-1131.
Dr Hsu has served on advisory boards for AbbVie, Inc.; Amgen, Inc.; Eli Lilly and Company; Janssen Pharmaceuticals, Inc.; Novartis AG; and Sun Pharmaceutical Industries Limited; and she has conducted research on behalf of Celgene Corporation and Novartis AG.