Q&A: Identifying and treating psoriasis in primary care

Psoriasis is a complex condition affecting the skin and the immune system, and it may also be linked to cardiovascular disease, anxiety, depression and arthritis. When managing patients, primary care practitioners should be aware of the conditions that mimic psoriasis and the various types of treatments available.

“I think we’re headed toward more and more targeted medications that will better isolate the effect on the psoriasis molecules alone, while leaving the rest of the body’s immune system to itself,” Robert Sidbury, MD, chief of the dermatology department at Seattle Children’s Hospital. “This will improve the risk-benefit ratio and the profile of medications. I think that’s where we’re headed at warp speed right now.”

Sidbury spoke with Healio Internal Medicine about making the diagnosis of psoriasis, choosing a treatment for children and adults, and comorbidities to consider. – by Jennifer Byrne

How do you make the differential diagnosis of psoriasis?

Psoriasis is common enough that many dermatologists make the diagnosis based only on a visual exam and a history. However, sometimes it’s not as simple as that — there are certain conditions that can mimic psoriasis that we keep in mind.

From a physical exam standpoint, when psoriasis is something we suspect, we always think about the distribution of the rash — there are certain areas that are more suggestive of psoriasis in both adults and kids. Those would be the umbilicus, which is fairly distinctive, the intergluteal cleft on the lower back and sacrum, the palms and soles, the scalp, fingernails and toenails. These all have distinctive changes that are different from mimics. We’ll look for those areas with psoriasis in mind and then we will also possibly entertain the possibility of a skin biopsy, which can show some specific findings.

We also take not just a personal history, but a family history, since psoriasis does run in families.

Finally, once we’ve accumulated those data, we’ll put them up against a list of conditions that can look like psoriasis, like atopic dermatitis or eczema, and seborrheic dermatitis, which has a fair degree of overlap with psoriasis, particularly in the head and neck. In fact, sometimes if we only see involvement that looks like psoriasis in the scalp, we might blend those terms and call it “sebopsoriasis,” because it has such a similar look to seborrheic dermatitis. When they’re overlapping that much and it’s just on the head and neck, we might use that term.

Another thing we’d definitely want to rule out is a fungal infection, because that can look a lot like psoriasis. There’s a condition called pityriasis rubra pilaris, or PRP, which looks a lot like psoriasis.

What medications might trigger flare-ups of psoriasis?

This isn’t something we often see in pediatrics, but probably the most notorious are beta blockers. That whole class of drugs is suspect. Another one I would call out — these are sort of counterintuitive — are the tumor necrosis factor (TNF) inhibitors. The reason this is counterintuitive is because they are also a treatment for psoriasis.

It’s so easy not to suspect them, because we use things like Enbrel (etanercept, Amgen) to treat bad psoriasis. Yet, in a certain population, particularly patients with inflammatory bowel disease, which is also treated with this same class of medications, the patient might get really bad refractory psoriasis, which is related to the medicine. So, these patients are diagnosed with Crohn’s disease or ulcerative colitis, and they’re treated with a TNF blocker like etanercept or one of the other drugs in that class, and they develop this severe psoriasis, even though they’ve never had it a day in their lives. This is important to remember.

What are some of the common comorbidities seen in psoriasis patients?

Associations between psoriasis and cardiovascular deaths and stroke have really become a big area of investigation in the last few years. The literature has gotten pretty strong in adults, and there’s even been some literature in pediatrics. There have been imaging studies to look at the vessels of pediatric patients with psoriasis, and there’s some suggestion that there is even earlier atherosclerotic change in the vessels of kids with psoriasis, although that is not as well established.

There was a paper published recently in JAMA Dermatology discussing guidelines for the screening of comorbidities in pediatric patients with psoriasis. These didn’t call out cardiovascular disease as much. It was discussed and viewed as an evolving comorbidity to consider, but the ones that were specified in addition to normal screening that pediatricians would do were depression, anxiety and arthritis. Obesity and metabolic syndrome were also mentioned as evolving comorbidities for that population.

For adult patients, I think cardiovascular disease should be mentioned and considered.

What is your first line approach to treating patients with psoriasis?

When the disease is localized and not impacting the patient enough to warrant systemic therapy, we would always much prefer to start with topical therapy. The classes of topical agents might include topical corticosteroids, topical vitamin D analogues such as calcipotriene, topical vitamin A analogues such as tazarotene, or tar derivatives. Tar is a time-honored treatment for psoriasis. There are products that are combinations of these various classes. For instance, there is a product called Taclonex (calcipotriene/betamethasone dipropionate, Leo Pharma), which is a combination of a steroid and a vitamin D product.

Also in the topical realm, we’ll use shampoos because of the characteristic scalp involvement. We’ll use anti-seborrheic or anti-dandruff shampoos, the sorts you can get over the counter like Head & Shoulders (Procter & Gamble) and Selsun (Sanofi) and T-Gel (Johnson & Johnson). We’ll also sometimes prescribe antifungal shampoos, one called ketoconazole, not so much because this is a fungal or infectious process, but because the yeast that we all have in our scalps seems to drive psoriasis a little bit.

Then, a quasi-topical treatment that can be used independently or as a bridge to or from systemic therapy is phototherapy. Phototherapy is employed much more commonly for adults than children, but can be a very effective treatment modality especially when involvement is diffusing. A modified version of phototherapy involving topical tar treatment in combination is called Goeckerman therapy. This is a very involved protocol that requires considerable investment of time and resources on both patient and provider part and this reality has limited the number of places that still offer the Goeckerman regimen (eg, UCSF Psoriasis Day Treatment Center).    

What types of systemic therapies are currently used?

The most time-honored systemic treatment, which I still use a lot in kids — although it’s generally used less and less now — is methotrexate. Another one in that class is cyclosporine.

Then there is the class of medications that has supplanted these: the biologic medications. These are more targeted to specific molecules so at least putatively they would have a better therapeutic to side effect ratio. However, this is the class of medicine that I mentioned that can induce psoriasis. Some of the drugs in this class are etanercept and Remicade (infliximab, Janssen Biotech), which is received by infusion. Etanercept is given as a subcutaneous injection. These are very expensive and generally more effective.

What are some of the differences in treating adult vs. pediatric psoriasis patients?

I think in pediatrics, we’re definitely more conservative by nature in treatment, whether we’re talking about psoriasis or anything else. So it generally does take a little bit more time for a pediatric dermatologist to initiate treatment with a systemic medication, especially one that is relatively new, like these biologics are, and don’t have a long track record of safety. That makes pediatricians very nervous for a number of reasons, not the least of which is that these kids are not really advocating for themselves yet, so we want to advocate for them.

Another thing we have to keep in mind is that psoriasis can have a tremendous impact on quality of life in kids. An objective way to decide if a patient needs systemic therapy is to say, “Okay, what’s their body surface area of involvement, and how severe is this psoriasis?” We do that in pediatrics too, but with kids, we also want to ask, “How much is this bothering you?” and let that help determine whether or not it is appropriate to court greater risk with the systemic medications.

At what point should a primary care physician refer a psoriasis patient to a dermatologist?

I’d say if the primary care doctor is starting to become unsure that the diagnosis is correct, that they’ve treated the condition as psoriasis in a way they should and it doesn’t respond. Refractoriness to treatment is a valid reason to refer, both as an independent reason and as cause to question the diagnosis of psoriasis. There might not be any question, the primary care doctor might be 100% correct. But when things don’t get better, you have to step back and say, “Well, wait a minute. Am I really treating what I think I’m treating?”

Referral as a means of expanding the treatment armamentarium is also a good reason, in terms of medications that a primary care doctor might not be as familiar or comfortable with, like the biologics or phototherapy.

Are there drug/drug interactions to be aware of?

I think the medications we cited earlier, the ones that induce psoriasis, would probably be on that list. There are certainly medications that are concerning in combination with alcohol consumption, like methotrexate, because of the potential double hit to the liver. Also with methotrexate, you need to be careful with other drugs that can potentially be metabolized that way, so we’re really careful with sulfa drugs in patients on methotrexate. We’re really not thrilled with these patients taking sulfa drugs.

In a similar vein, taking a lot of ibuprofen or nonsteroidal drugs in combination with cyclosporine or any drug that can be challenging to the kidney is something to avoid. It’s not an absolute contraindication by any stretch, but it’s something you want to consider. You want to look at what organ the psoriasis drug is potentially able to harm, and then think carefully about any other drugs that might harm that same organ.

Another risk that tends to be forgotten, although it’s not quite a drug-drug interaction, is that you always want to consider a TB screening before starting patients on these immunosuppressant medications like biologics or methotrexate or cyclosporine. You don’t want to have latent TB unmasked by one of these drugs; that is something that can happen.

Where do you think the future of psoriasis treatment is headed?

I think as with all medication, these days there’s better learning about the genetic basis of the disease itself. We know much more about psoriasis genetics now, but it’s crazy the number of genes that have been associated with psoriasis. It’s almost hard to engage and truly personalize medicine yet because there are so many genes that are associated, but I think that will change. We’ll get a better ability to sort the wheat from the chaff, genetically speaking, and that too will allow us to personalize the treatment and improve things.

Another thing I’d like to mention, that comes up a fair bit in kids, is a form of psoriasis called guttate psoriasis. Rather than presenting as large plaques on the elbows and knees, this comes as a shower of smaller ovals, maybe2 mm to 1 cm plaques on the trunk and extremities. It can occur in adults, but it’s more common in kids. When we see that type of psoriasis, we think about the possibility that the patient has recently had a strep throat, because the body’s immune reaction to Streptococcus is notorious for being a trigger of that type of psoriasis. That piece of data has been extrapolated now to a promising treatment for psoriasis, which is tonsillectomy. There have been studies done, most notably in Iceland in adults, in which patients with psoriasis get tonsillectomy, because the tonsils are lymphoid tissue that can be harboring these immune cells that then go forth and trigger psoriasis.

The literature isn’t strong enough that I will say, “You’ve got psoriasis? Well, automatically you need a tonsillectomy,” but I did want to mention it, because I think primary care doctors and family doctors probably haven’t heard of this. If there’s a patient with any other indication for a tonsillectomy that might not be strong enough on its own — such as snoring or recurrent strep throat — but they also have psoriasis, that may be reason to justify this relatively safe, though not trivial, procedure, and accomplish several different missions.

References:

Osier E, et al. JAMA Dermatol. 2017;doi:10.1001/jamadermatol.2017.0499.

Thorleifsdottir RH, et al. J Am Acad Dermatol. 2016;doi:10.1016/j.jaad.2016.06.061.

For More Information: Robert Sidbury, MD, can be reached at 4800 Sand Point Way NE Seattle, WA 98105; email: robert.sidbury@seattlechildrens.org.

Disclosure: Sidbury reports no relevant disclosures.

Psoriasis is a complex condition affecting the skin and the immune system, and it may also be linked to cardiovascular disease, anxiety, depression and arthritis. When managing patients, primary care practitioners should be aware of the conditions that mimic psoriasis and the various types of treatments available.

“I think we’re headed toward more and more targeted medications that will better isolate the effect on the psoriasis molecules alone, while leaving the rest of the body’s immune system to itself,” Robert Sidbury, MD, chief of the dermatology department at Seattle Children’s Hospital. “This will improve the risk-benefit ratio and the profile of medications. I think that’s where we’re headed at warp speed right now.”

Sidbury spoke with Healio Internal Medicine about making the diagnosis of psoriasis, choosing a treatment for children and adults, and comorbidities to consider. – by Jennifer Byrne

How do you make the differential diagnosis of psoriasis?

Psoriasis is common enough that many dermatologists make the diagnosis based only on a visual exam and a history. However, sometimes it’s not as simple as that — there are certain conditions that can mimic psoriasis that we keep in mind.

From a physical exam standpoint, when psoriasis is something we suspect, we always think about the distribution of the rash — there are certain areas that are more suggestive of psoriasis in both adults and kids. Those would be the umbilicus, which is fairly distinctive, the intergluteal cleft on the lower back and sacrum, the palms and soles, the scalp, fingernails and toenails. These all have distinctive changes that are different from mimics. We’ll look for those areas with psoriasis in mind and then we will also possibly entertain the possibility of a skin biopsy, which can show some specific findings.

We also take not just a personal history, but a family history, since psoriasis does run in families.

PAGE BREAK

Finally, once we’ve accumulated those data, we’ll put them up against a list of conditions that can look like psoriasis, like atopic dermatitis or eczema, and seborrheic dermatitis, which has a fair degree of overlap with psoriasis, particularly in the head and neck. In fact, sometimes if we only see involvement that looks like psoriasis in the scalp, we might blend those terms and call it “sebopsoriasis,” because it has such a similar look to seborrheic dermatitis. When they’re overlapping that much and it’s just on the head and neck, we might use that term.

Another thing we’d definitely want to rule out is a fungal infection, because that can look a lot like psoriasis. There’s a condition called pityriasis rubra pilaris, or PRP, which looks a lot like psoriasis.

What medications might trigger flare-ups of psoriasis?

This isn’t something we often see in pediatrics, but probably the most notorious are beta blockers. That whole class of drugs is suspect. Another one I would call out — these are sort of counterintuitive — are the tumor necrosis factor (TNF) inhibitors. The reason this is counterintuitive is because they are also a treatment for psoriasis.

It’s so easy not to suspect them, because we use things like Enbrel (etanercept, Amgen) to treat bad psoriasis. Yet, in a certain population, particularly patients with inflammatory bowel disease, which is also treated with this same class of medications, the patient might get really bad refractory psoriasis, which is related to the medicine. So, these patients are diagnosed with Crohn’s disease or ulcerative colitis, and they’re treated with a TNF blocker like etanercept or one of the other drugs in that class, and they develop this severe psoriasis, even though they’ve never had it a day in their lives. This is important to remember.

What are some of the common comorbidities seen in psoriasis patients?

Associations between psoriasis and cardiovascular deaths and stroke have really become a big area of investigation in the last few years. The literature has gotten pretty strong in adults, and there’s even been some literature in pediatrics. There have been imaging studies to look at the vessels of pediatric patients with psoriasis, and there’s some suggestion that there is even earlier atherosclerotic change in the vessels of kids with psoriasis, although that is not as well established.

There was a paper published recently in JAMA Dermatology discussing guidelines for the screening of comorbidities in pediatric patients with psoriasis. These didn’t call out cardiovascular disease as much. It was discussed and viewed as an evolving comorbidity to consider, but the ones that were specified in addition to normal screening that pediatricians would do were depression, anxiety and arthritis. Obesity and metabolic syndrome were also mentioned as evolving comorbidities for that population.

For adult patients, I think cardiovascular disease should be mentioned and considered.

PAGE BREAK

What is your first line approach to treating patients with psoriasis?

When the disease is localized and not impacting the patient enough to warrant systemic therapy, we would always much prefer to start with topical therapy. The classes of topical agents might include topical corticosteroids, topical vitamin D analogues such as calcipotriene, topical vitamin A analogues such as tazarotene, or tar derivatives. Tar is a time-honored treatment for psoriasis. There are products that are combinations of these various classes. For instance, there is a product called Taclonex (calcipotriene/betamethasone dipropionate, Leo Pharma), which is a combination of a steroid and a vitamin D product.

Also in the topical realm, we’ll use shampoos because of the characteristic scalp involvement. We’ll use anti-seborrheic or anti-dandruff shampoos, the sorts you can get over the counter like Head & Shoulders (Procter & Gamble) and Selsun (Sanofi) and T-Gel (Johnson & Johnson). We’ll also sometimes prescribe antifungal shampoos, one called ketoconazole, not so much because this is a fungal or infectious process, but because the yeast that we all have in our scalps seems to drive psoriasis a little bit.

Then, a quasi-topical treatment that can be used independently or as a bridge to or from systemic therapy is phototherapy. Phototherapy is employed much more commonly for adults than children, but can be a very effective treatment modality especially when involvement is diffusing. A modified version of phototherapy involving topical tar treatment in combination is called Goeckerman therapy. This is a very involved protocol that requires considerable investment of time and resources on both patient and provider part and this reality has limited the number of places that still offer the Goeckerman regimen (eg, UCSF Psoriasis Day Treatment Center).    

What types of systemic therapies are currently used?

The most time-honored systemic treatment, which I still use a lot in kids — although it’s generally used less and less now — is methotrexate. Another one in that class is cyclosporine.

Then there is the class of medications that has supplanted these: the biologic medications. These are more targeted to specific molecules so at least putatively they would have a better therapeutic to side effect ratio. However, this is the class of medicine that I mentioned that can induce psoriasis. Some of the drugs in this class are etanercept and Remicade (infliximab, Janssen Biotech), which is received by infusion. Etanercept is given as a subcutaneous injection. These are very expensive and generally more effective.

What are some of the differences in treating adult vs. pediatric psoriasis patients?

I think in pediatrics, we’re definitely more conservative by nature in treatment, whether we’re talking about psoriasis or anything else. So it generally does take a little bit more time for a pediatric dermatologist to initiate treatment with a systemic medication, especially one that is relatively new, like these biologics are, and don’t have a long track record of safety. That makes pediatricians very nervous for a number of reasons, not the least of which is that these kids are not really advocating for themselves yet, so we want to advocate for them.

Another thing we have to keep in mind is that psoriasis can have a tremendous impact on quality of life in kids. An objective way to decide if a patient needs systemic therapy is to say, “Okay, what’s their body surface area of involvement, and how severe is this psoriasis?” We do that in pediatrics too, but with kids, we also want to ask, “How much is this bothering you?” and let that help determine whether or not it is appropriate to court greater risk with the systemic medications.

PAGE BREAK

At what point should a primary care physician refer a psoriasis patient to a dermatologist?

I’d say if the primary care doctor is starting to become unsure that the diagnosis is correct, that they’ve treated the condition as psoriasis in a way they should and it doesn’t respond. Refractoriness to treatment is a valid reason to refer, both as an independent reason and as cause to question the diagnosis of psoriasis. There might not be any question, the primary care doctor might be 100% correct. But when things don’t get better, you have to step back and say, “Well, wait a minute. Am I really treating what I think I’m treating?”

Referral as a means of expanding the treatment armamentarium is also a good reason, in terms of medications that a primary care doctor might not be as familiar or comfortable with, like the biologics or phototherapy.

Are there drug/drug interactions to be aware of?

I think the medications we cited earlier, the ones that induce psoriasis, would probably be on that list. There are certainly medications that are concerning in combination with alcohol consumption, like methotrexate, because of the potential double hit to the liver. Also with methotrexate, you need to be careful with other drugs that can potentially be metabolized that way, so we’re really careful with sulfa drugs in patients on methotrexate. We’re really not thrilled with these patients taking sulfa drugs.

In a similar vein, taking a lot of ibuprofen or nonsteroidal drugs in combination with cyclosporine or any drug that can be challenging to the kidney is something to avoid. It’s not an absolute contraindication by any stretch, but it’s something you want to consider. You want to look at what organ the psoriasis drug is potentially able to harm, and then think carefully about any other drugs that might harm that same organ.

Another risk that tends to be forgotten, although it’s not quite a drug-drug interaction, is that you always want to consider a TB screening before starting patients on these immunosuppressant medications like biologics or methotrexate or cyclosporine. You don’t want to have latent TB unmasked by one of these drugs; that is something that can happen.

Where do you think the future of psoriasis treatment is headed?

I think as with all medication, these days there’s better learning about the genetic basis of the disease itself. We know much more about psoriasis genetics now, but it’s crazy the number of genes that have been associated with psoriasis. It’s almost hard to engage and truly personalize medicine yet because there are so many genes that are associated, but I think that will change. We’ll get a better ability to sort the wheat from the chaff, genetically speaking, and that too will allow us to personalize the treatment and improve things.

PAGE BREAK

Another thing I’d like to mention, that comes up a fair bit in kids, is a form of psoriasis called guttate psoriasis. Rather than presenting as large plaques on the elbows and knees, this comes as a shower of smaller ovals, maybe2 mm to 1 cm plaques on the trunk and extremities. It can occur in adults, but it’s more common in kids. When we see that type of psoriasis, we think about the possibility that the patient has recently had a strep throat, because the body’s immune reaction to Streptococcus is notorious for being a trigger of that type of psoriasis. That piece of data has been extrapolated now to a promising treatment for psoriasis, which is tonsillectomy. There have been studies done, most notably in Iceland in adults, in which patients with psoriasis get tonsillectomy, because the tonsils are lymphoid tissue that can be harboring these immune cells that then go forth and trigger psoriasis.

The literature isn’t strong enough that I will say, “You’ve got psoriasis? Well, automatically you need a tonsillectomy,” but I did want to mention it, because I think primary care doctors and family doctors probably haven’t heard of this. If there’s a patient with any other indication for a tonsillectomy that might not be strong enough on its own — such as snoring or recurrent strep throat — but they also have psoriasis, that may be reason to justify this relatively safe, though not trivial, procedure, and accomplish several different missions.

References:

Osier E, et al. JAMA Dermatol. 2017;doi:10.1001/jamadermatol.2017.0499.

Thorleifsdottir RH, et al. J Am Acad Dermatol. 2016;doi:10.1016/j.jaad.2016.06.061.

For More Information: Robert Sidbury, MD, can be reached at 4800 Sand Point Way NE Seattle, WA 98105; email: robert.sidbury@seattlechildrens.org.

Disclosure: Sidbury reports no relevant disclosures.