Why Do Psoriasis Treatments Sometimes Stop Working?

Here’s an overview of different psoriasis treatments, and how likely they are to lose effectiveness over time — either because of how your psoriasis changes, or because of changes to how your body responds to the treatment itself.

While it’s possible for any psoriasis treatment to become less effective at controlling symptoms in a specific person at some point in time, there may be confusion about how common this is, and why it happens. That’s especially the case with topical steroids.

“There is a controversial phenomenon called tachyphylaxis, where topical treatments, particularly topical steroids, are purported to lose effectiveness over time,” says Melvin Chiu, MD, a dermatologist at Keck Medicine of USC in Los Angeles. “There is little evidence to support this actually happens.”

Dr. Chiu says there may actually be other things happening: The effectiveness of a topical steroid may stay the same while someone’s psoriasis gets worse. It’s also possible, he says, for someone to use a treatment inconsistently and perceive this as a lack of efficacy.

“Topical therapy typically doesn’t work well for psoriasis as a singular treatment,” which means that an increase in psoriasis activity can quickly overwhelm topical steroids, says Matt Lewis, MD, MPH, a dermatologist at Stanford Medicine in Redwood City, California. “You can get biological resistance to other medications, but it’s not observed in psoriasis with topical steroids,” he says, over decades of research.

Systemic corticosteroids are “not a mainstay of psoriasis treatment,” says Lewis, so there isn’t much evidence about their effectiveness over time. But when they are used, he says, “We don’t see them losing effectiveness.”

Unlike with other psoriasis treatments, there is clear evidence that many biologic drugs tend to become less effective over time.

Biologic drugs are structurally similar to hormones or other components in the human body, which is central to their possible loss of efficacy. “Biologics lose effectiveness over time because the immune system in some patients learns to recognize the biologics as foreign material and develops mechanisms to neutralize the biologics,” says Chiu.

It generally takes at least 6 months, and usually at least 1 to 2 years, for biologic drugs to start losing their effectiveness in a significant way in psoriasis, Lewis says. But even when a drug becomes less effective, it may still be effective enough for a while before a patient and doctor decide to switch to another drug.

The good news is that resistance to biologics is not a class effect, meaning that it won’t apply to another drug in the same class — such as TNF inhibitors or IL-17 inhibitors. “So we could switch to another biologic in that class, or we might switch classes if we’ve exhausted the best options in that class,” says Lewis.

Sometimes a biologic drug will start to wear off before someone’s next dose is due, Lewis says, but that’s not the same thing as your body becoming less responsive to the drug over time. Usually, he says, this effect is mild, and people can either tolerate their psoriasis symptoms or use topical drugs to control them until their next dose of a biologic is due.

There isn’t clear evidence that any other drugs used to treat psoriasis lose effectiveness over time, even though they may be perceived to do so.

“Traditional systemic treatments for psoriasis such as acitretin, cyclosporine, and methotrexate don’t typically lose effectiveness, but are mostly limited by their overall effectiveness or side effects,” says Chiu. In other words, they may not be effective enough to control your symptoms when your psoriasis activity increases, or people may not take them consistently due to side effects.

If you observe that your psoriasis treatment is no longer effective, that could mean it’s time to switch to a different treatment that has been shown to be more effective overall in clinical trials.

“We’re pretty lucky that we have so many effective treatment options for psoriasis,” says Lewis. “The biologics are incredibly effective, and the available options are going to keep growing.

• While there’s little evidence that topical therapies lose effectiveness, it is known that topical therapies alone often aren’t enough to fully control psoriasis.
• Biologic medications can lose effectiveness over time because the immune system can learn to neutralize them, but alternatives are available within similar drug classes.
• If your psoriasis treatment seems to lose effectiveness, talk to your healthcare provider about a possible switch to another treatment that has been proven more effective in clinical trials.