The major comorbidities that I try to cover in the review of systems and medical history are psoriatic arthritis, IBD, congestive heart failure, and, to some extent, uveitis and multiple sclerosis. Psoriatic arthritis is the top comorbidity to actively screen our patients for, and interleukin-17 (IL-17) inhibitors would be my preference in patients with psoriatic arthritis and no other comorbidities. Other biologics would not be expected to exacerbate psoriatic arthritis, but they might not have the same efficacy.

In the treatment of plaque psoriasis, you would avoid the IL-17 inhibitors in patients with IBD because they can exacerbate it or contribute to that risk. The tumor necrosis factor (TNF), IL-12/23, and IL-23 inhibitors require the least amount of worry in individuals with IBD. You can start the patient on treatment without much concern about whether you are going to make them worse in certain respects.

In those with congestive heart failure or multiple sclerosis, you would steer away from a TNF inhibitor. In contrast, you might gravitate toward a TNF inhibitor in someone with comorbid uveitis, as TNF inhibitors are likely the most effective for uveitis. Special circumstances include a history of tuberculosis, in which case you would not use a TNF inhibitor. Another special circumstance is pregnancy, and, in women who are either trying to conceive or are pregnant, a TNF inhibitor such as certolizumab may be more appropriate because it does not cross the placenta.

Overall, I am also not using TNF inhibitors for the treatment of psoriasis as much, although certolizumab might be an apt choice for a woman of childbearing potential. I might also consider using a TNF blocker in a patient with both hidradenitis suppurativa and psoriasis.

As Dr Strober alluded to, IBD can be an issue with the IL-17 inhibitors. I had a patient not too long ago who was doing very well on the IL-17 blocker secukinumab and had no problems whatsoever. Incidental Crohn’s disease was detected during a routine colonoscopy, so we had to stop the secukinumab and we started guselkumab. And, fast forward, the patient’s joints continued to do fine and their skin stayed clear despite being off therapy for a bit while we were in the approval process. Further, when the patient went back for a 2-year follow-up for a repeat colonoscopy, it was discovered that the Crohn’s disease was essentially gone.

IBD usually develops years after psoriasis is diagnosed, much like psoriatic arthritis, so, in addition to dermatologists asking their patients with psoriasis about joint stiffness, they should also be asking questions about the presence of diarrhea, chronic diarrhea, and blood in the stool, among other issues, on a regular basis because these patients may develop IBD down the road.

Now, IL-17 inhibitors do have a place when you need something fast. For example, if a patient comes in with generalized pustular psoriasis—which I do not see too often—you want to prescribe a drug that is fast acting. You can start them on cyclosporin, of course, but I think that an IL-17 inhibitor such as ixekizumab might be a good option in that case because it does work very fast.

IL-23 inhibitors are central to the pathophysiology of psoriasis, and, when you look at the genetics of psoriasis, you find that IL-23–related genes are linked to psoriasis. IL-23 inhibitors are very effective, safe drugs, so I will use them as first-line therapy in most situations that require systemic therapy. If a patient with plaque psoriasis has some joint discomfort, I have no problem starting an IL-23 inhibitor, and I look to the patient’s rheumatologist to evaluate their joints and to perform the assessments to determine whether a change in therapy or additional treatment might be needed.

Some believe that we should avoid prescribing the IL-17 inhibitors completely in patients who are at risk for IBD. I think that the IL-17 inhibitors have the advantage of being fast acting, but they have the disadvantage of potentially causing or exacerbating IBD. Unless a patient desperately wants the fastest-acting drug, which some do, I would likely favor using an IL-23 inhibitor marginally over an IL-17 drug.

In general, I think of TNF inhibitors as being a third-line treatment for psoriasis, behind the IL-23 and IL-17 inhibitors. TNF inhibitors are approved by the US Food and Drug Administration for psoriatic arthritis, but many people with psoriasis and psoriatic arthritis experience an improvement in their psoriatic arthritis on other systemic therapies. When choosing among the drugs, you need to balance multiple factors; the presence of psoriatic arthritis does not, by itself, make me choose one treatment over another.