The management of psoriasis has changed considerably over the past two decades. We used to use tar and anthralin for limited disease and methotrexate and PUVA for extensive psoriasis. Now we have treatments that are more effective, less messy, less risky and more convenient.
In parallel with the changing in treatments, the measures we use to assess psoriasis and treatment success have been changing, too. While the Psoriasis Area and Severity Index (PASI) is still an important tool, we have gone from considering a 75% improvement in PASI to a 90% (or even 100% improvement) as a suitable measure of success.
And PASI—a measure of the redness, thickness and scaliness of the plaques—is, more and more, complemented by patient-reported outcomes. The Dermatology Life Quality Index (DLQI) has become a standard component of psoriasis trials, assessing patients’ quality of life and demonstrating that the observed objective improvements in disease severity are making a clinically meaningful difference in patients’ lives.
The move toward more patient-centered disease severity measurement has extended to the development of a variety of validated tools for assessing the specific symptoms associated with psoriasis, including patients’ perceptions of pain, itch and flaking.
My training in dermatology is founded in basic sciences: biochemistry, cell biology, immunology, pharmacology, histopathology, clinical dermatology and epidemiology. But just as the measures used to assess psoriasis have extended into patient-reported outcomes, I find the practice of psoriasis management relies less & less on that foundation and more & more on human psychology, a field that wasn’t stressed enough in my medical training.
Psoriasis treatment should be guided by an understanding of patients’ goals and perceptions. Assessing these in the clinical setting is more difficult than measuring skin levels of interleukins 23 and 17; teasing out what patients want, often obscured by their lack of candor, is an art that as yet I am not an expert. And while it may be easy to know that our treatments can safely give patients tremendous improvement, getting them to accept and use those treatments is an enormous conundrum that benefits little from a foundation in biochemistry, cell biology, immunology, pharmacology, histopathology, clinical dermatology and epidemiology. How we present objective information to patients will be interpreted through very subjective lenses. How to manipulate those perceptions to give patients the best guidance and outcomes is not yet at all well understood.
While new drugs for psoriasis and skin disease continue to be developed, the next great frontier of scientific advances that will benefit our patients may come from a better understanding and application of human psychology.