What is topical in psoriasis?

The AAD and NPF released new guidelines for treatment of psoriasis with topical therapy

Despite dramatic advances in our therapeutic armamentarium for managing psoriasis with pills and biologics, topical therapies remain the most commonly used arrow in our therapeutic quiver.

First, 80% of patients with psoriasis have limited body surface area involved and thus are candidates for topical therapy. Second, even our best treatments for patients with moderate to severe psoriasis will fail to achieve 100% clearance in a large percentage of patients. Thus, dermatologists must master both the art and science of the use of topical therapies to manage psoriasis. The American Academy of Dermatology and the National Psoriasis Foundation recently released new guidelines about management of psoriasis with topical therapies from which I harvested and polished a few pearls for you in this commentary. Full disclosure: I am one of the authors of these guidelines.

Ultrapotent corticosteroids (class 1) have efficacy rates varying from 58% to 92%. In high-potency corticosteroids (class 2 and 3), the efficacy rates vary from 68% to 74%. Vehicle control responses vary from 15% to 30%. The substantial vehicle response is a reminder that patients with psoriasis should be encouraged to use bland emollients on a regular basis. Of course, we are all aware of the local side effects of topical steroids: Atrophy, folliculitis, telangiectasia, bruising and striae. The guidelines point out that suppression of the hypothalamic-pituitary-adrenal (HPA) axis can occur in up to 48% of patients treated with ultrapotent steroids (I am talking to you, clobetasol). While HPA suppression is rarely clinically significant, these findings are an important reminder that we must use topical steroids judiciously.

Topical calcineurin inhibitors are effective for psoriasis, particularly for facial and intertriginous psoriasis, but are not FDA approved for this indication. Although these agents carry a black box warning for cancer, the guidelines conclude that there is no evidence showing an increased risk for malignancy with topical pimecrolimus or tacrolimus. Topical vitamin D agents have a role to play, primarily as a steroid-sparing agent or to enhance efficacy of a steroid in a combination product. Topical vitamin A derivatives such as tazarotene have some efficacy as well and may be more useful when combined in a single once-a-day lotion with halobetasol. However, tazarotene has warnings about use in pregnancy, and the combination (halobetasol 0.01%/tazarotene 0.045%) product label advises prescribers to check a pregnancy test within 2 weeks of starting treatment in women of childbearing potential.

The main advances we have seen in topical therapies since our last guidelines about one decade ago are improvements in vehicles such as foams and sprays that make the use of topical agents more acceptable to patients. Novel topical agents for psoriasis are on the horizon, including JAK and PDE4 inhibitors, and will hopefully add arrows with new mechanisms of action to our therapeutic quiver for psoriasis.

References:

Elmets CA, et al. J Am Acad Dermatol. 2020;doi:10.1016/j.jaad.2020.07.087.

Solimani F, et al. Front Immunol. 2019;doi:10.3389/fimmu.2019.02847.